Dr Farzin Ghanadi

Dr Farzin Ghanadi

Research Associate

School of Engineering

Career Summary

Biography

Lecturer, researcher and consultant in experimental/numerical fluid mechanics and aerodynamics with the application in aerospace engineering, wind engineering and renewable energy.

Qualifications

  • Doctor of Philosophy, University of Adelaide

Keywords

  • Experimental and Computational Fluid Dynamic
  • Fluid Mechanics
  • Mechanical Engineering
  • Turbulence

Languages

  • English (Fluent)

Fields of Research

Code Description Percentage
091599 Interdisciplinary Engineering not elsewhere classified 40
091399 Mechanical Engineering not elsewhere classified 60

Professional Experience

UON Appointment

Title Organisation / Department

Academic appointment

Dates Title Organisation / Department
10/2/2015 - 26/5/2019 Research Associate University of Adelaide
Mechanical Engineering
Edit

Publications

For publications that are currently unpublished or in-press, details are shown in italics.


Journal article (21 outputs)

Year Citation Altmetrics Link
2020 Jafari A, Emes M, Cazzolato B, Ghanadi F, Arjomandi M, 'Turbulence characteristics in the wake of a heliostat in an atmospheric boundary layer flow', Physics of Fluids, 32 (2020) [C1]
DOI 10.1063/5.0005594
2020 Pourmehran O, Arjomandi M, Cazzolato B, Ghanadi F, Tian Z, 'The impact of geometrical parameters on acoustically driven drug delivery to maxillary sinuses', Biomechanics and Modeling in Mechanobiology, 19 557-575 (2020)
DOI 10.1007/s10237-019-01230-5
Citations Scopus - 1
2020 Torres JF, Ghanadi F, Wang Y, Arjomandi M, Pye J, 'Mixed convection and radiation from an isothermal bladed structure', INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 147 (2020)
DOI 10.1016/j.ijheatmasstransfer.2019.118906
Citations Scopus - 1Web of Science - 1
2019 Yu JS, Emes MJ, Ghanadi F, Arjomandi M, Kelso R, 'Experimental investigation of peak wind loads on tandem operating heliostats within an atmospheric boundary layer', SOLAR ENERGY, 183 248-259 (2019)
DOI 10.1016/j.solener.2019.03.002
Citations Scopus - 1Web of Science - 1
2019 Jafari A, Ghanadi F, Emes MJ, Arjomandi M, Cazzolato BS, 'Measurement of unsteady wind loads in a wind tunnel: Scaling of turbulence spectra', JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS, 193 (2019)
DOI 10.1016/j.jweia.2019.103955
Citations Scopus - 1Web of Science - 2
2019 Jafari A, Ghanadi F, Arjomandi M, Emes MJ, Cazzolato BS, 'Correlating turbulence intensity and length scale with the unsteady lift force on flat plates in an atmospheric boundary layer flow', JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS, 189 218-230 (2019)
DOI 10.1016/j.jweia.2019.03.029
Citations Scopus - 2Web of Science - 3
2019 Emes MJ, Jafari A, Ghanadi F, Arjomandi M, 'Hinge and overturning moments due to unsteady heliostat pressure distributions in a turbulent atmospheric boundary layer', SOLAR ENERGY, 193 604-617 (2019)
DOI 10.1016/j.solener.2019.09.097
Citations Scopus - 1Web of Science - 1
2019 Emes MJ, Arjomandi M, Kelso RM, Ghanadi F, 'Turbulence length scales in a low-roughness near-neutral atmospheric surface layer', JOURNAL OF TURBULENCE, 20 545-562 (2019) [C1]
DOI 10.1080/14685248.2019.1677908
2018 Torres JF, Ghanadi F, Nock I, Arjomandi M, Pye J, 'Mixed convection around a tilted cuboid with an isothermal sidewall at moderate Reynolds numbers', INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 119 418-432 (2018)
DOI 10.1016/j.ijheatmasstransfer.2017.11.109
Citations Scopus - 8Web of Science - 4
2018 Silvestri A, Ghanadi F, Arjomandi M, Cazzolato B, Zander A, 'The Application of Different Tripping Techniques to Determine the Characteristics of the Turbulent Boundary Layer Over a Flat Plate', JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME, 140 (2018)
DOI 10.1115/1.4037675
Citations Scopus - 4Web of Science - 4
2018 Emes MJ, Ghanadi F, Arjomandi M, Kelso RM, 'Investigation of peak wind loads on tandem heliostats in stow position', RENEWABLE ENERGY, 121 548-558 (2018)
DOI 10.1016/j.renene.2018.01.080
Citations Scopus - 6Web of Science - 5
2018 Silvestri A, Ghanadi F, Arjomandi M, Cazzolato B, Zander A, Chin R, 'Mechanism of sweep event attenuation using micro-cavities in a turbulent boundary layer', PHYSICS OF FLUIDS, 30 (2018)
DOI 10.1063/1.5026130
Citations Scopus - 1Web of Science - 1
2017 Lee KL, Jafarian M, Ghanadi F, Arjomandi M, Nathan GJ, 'An investigation into the effect of aspect ratio on the heat loss from a solar cavity receiver', SOLAR ENERGY, 149 20-31 (2017)
DOI 10.1016/j.solener.2017.03.089
Citations Scopus - 15Web of Science - 12
2017 Emes MJ, Arjomandi M, Ghanadi F, Kelso RM, 'Effect of turbulence characteristics in the atmospheric surface layer on the peak wind loads on heliostats in stow position', SOLAR ENERGY, 157 284-297 (2017)
DOI 10.1016/j.solener.2017.08.031
Citations Scopus - 12Web of Science - 10
2017 Silvestri A, Ghanadi F, Arjomandi M, Cazzolato B, Zander A, 'Attenuation of sweep events in a turbulent boundary layer using micro-cavities', EXPERIMENTS IN FLUIDS, 58 (2017)
DOI 10.1007/s00348-017-2345-7
Citations Scopus - 5Web of Science - 4
2017 Silvestri A, Ghanadi F, Arjomandi M, Chin R, Cazzolato B, Zander A, 'Attenuation of turbulence by the passive control of sweep events in a turbulent boundary layer using micro-cavities', PHYSICS OF FLUIDS, 29 (2017)
DOI 10.1063/1.4995466
Citations Scopus - 4Web of Science - 4
2015 Ghanadi F, Arjomandi M, Cazzolato BS, Zander AC, 'Analysis of the turbulent boundary layer in the vicinity of a self-excited cylindrical Helmholtz resonator', JOURNAL OF TURBULENCE, 16 705-728 (2015)
DOI 10.1080/14685248.2015.1024839
Citations Scopus - 9Web of Science - 7
2014 Ghanadi F, Arjomandi M, Cazzolato B, Zander A, 'Understanding of the flow behaviour on a Helmholtz resonator excited by grazing flow', INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS, 28 219-231 (2014)
DOI 10.1080/10618562.2014.922681
Citations Scopus - 11Web of Science - 5
2014 Akhavan A, Binesh F, Shamshiri H, Ghanadi F, 'Survival of Patients with Ewing's Sarcoma in Yazd-Iran', ASIAN PACIFIC JOURNAL OF CANCER PREVENTION, 15 4861-4864 (2014)
DOI 10.7314/APJCP.2014.15.12.4861
Citations Scopus - 4Web of Science - 4
2014 Ghanadi F, Arjomandi M, Cazzolato B, Zander A, 'Interaction of a flow-excited Helmholtz resonator with a grazing turbulent boundary layer', EXPERIMENTAL THERMAL AND FLUID SCIENCE, 58 80-92 (2014)
DOI 10.1016/j.expthermflusci.2014.06.016
Citations Scopus - 12Web of Science - 8
2013 Ghanadi F, Arjomandi M, Zander AC, Cazzolato BS, 'Numerical simulation of grazing flow over a self-excited Helmholtz resonator', Engineering Letters, 21 137-142 (2013)

Self-sustained oscillations of the grazing flow along the orifice of a Helmholtz resonator were considered numerically. These fluctuations are driven by hydrodynamic instabilities... [more]

Self-sustained oscillations of the grazing flow along the orifice of a Helmholtz resonator were considered numerically. These fluctuations are driven by hydrodynamic instabilities inside the shear layer and the resonant acoustical field. Quantitative prediction of this process requires accurate calculations of grazing flow characteristics over the three dimensional resonator. In this paper flow excitation phenomenon assumed to be associated with external pressure fluctuations within the turbulent boundary layer of grazing flow and acoustic response of the cavity. To this end a Large Eddy Simulation (LES) of the three dimensional shear flow over the orifice carried out at a low Mach number to allow predictions of the amplitude and frequency of the pressure and velocity fluctuations. For validation propose, for pressure fluctuations inside the cavity, a good quantitative agreement with published data was obtained. Therefore the simulations provide an ability to predict the resonating frequency, pressure and velocity field for different inlet conditions.

Citations Scopus - 2
Show 18 more journal articles

Conference (25 outputs)

Year Citation Altmetrics Link
2019 Pye J, Abbasi E, Arjomandi M, Coventry J, Ghanadi F, Hughes G, et al., 'Towards testing of a second-generation bladed receiver', AIP Conference Proceedings (2019)

© 2019 Author(s). A bladed receiver design concept is presented which offers a >2% increase in overall receiver efficiency after considering spillage, reflection, emission and ... [more]

© 2019 Author(s). A bladed receiver design concept is presented which offers a >2% increase in overall receiver efficiency after considering spillage, reflection, emission and convection losses, based on an integrated optical-thermal model, for a design where the working fluid is conventional molten salt operating in the standard 290-565°C temperature range. A novel testing methodology is described, using air and water to test the receiver when molten salt facilities are not available. Technoeconomic analysis shows that the receiver could achieve a 4 AUD/MWhe saving in levelised cost of energy, but only if the bladed receiver design can be implemented at no additional cost.

DOI 10.1063/1.5117556
Citations Scopus - 1
2019 Emes MJ, Jafari A, Ghanadi F, Arjomandi M, 'A method for the calculation of the design wind loads on heliostats', AIP Conference Proceedings (2019)

© 2019 Author(s). This experimental study outlines a method to calculate the design wind loads on heliostats, based on peak wind load coefficients reported in the heliostat litera... [more]

© 2019 Author(s). This experimental study outlines a method to calculate the design wind loads on heliostats, based on peak wind load coefficients reported in the heliostat literature and aerodynamic shape factors derived from high-frequency pressure measurements on an isolated heliostat at different elevation and azimuth angles in a boundary layer wind tunnel. The results show that the aerodynamic shape factors are largest for a range of heliostat configurations, including elevation angles of 15°, 30° and 45°and azimuth angles of 0° and 45°. The distribution of shape factors indicates that the leading edge of the heliostat is most vulnerable to wind-induced mirror damage in this range of critical elevation angles for heliostat design wind loads. The method proposed in the current study for heliostats conforms to the procedure used in design wind codes and standards for buildings and roof-mounted solar panels.

DOI 10.1063/1.5117532
Citations Scopus - 1
2019 Torres JF, Ghanadi F, Arjomandi M, Pye J, 'Convective heat loss from a bladed solar receiver', AIP Conference Proceedings (2019)

© 2019 Author(s). Alternative structures have been proposed to improve light trapping and reduce radiative heat losses from central tower receivers. Bladed, star-shaped, and spike... [more]

© 2019 Author(s). Alternative structures have been proposed to improve light trapping and reduce radiative heat losses from central tower receivers. Bladed, star-shaped, and spiked receivers are candidates with a potential to improve light trapping and reduce thermal emissions. Of interest is the bladed receiver concept due to its ease of optical performance tuning and potential application to a diversity of receivers from central tower (surround field) to billboard (polar field) types. Although fractal-like receivers improve optical performance, a possible increase of convective heat losses due to extended surface effects could overshadow these improvements. Quantifying convective heat loss from solar receivers is a challenging task due to the nonlinearity of mixed convection, variable wind conditions and turbulence. In this study, we conducted a thorough computational fluid dynamics analysis of convective heat losses from a bladed receiver and show that the blades may actually decrease convective heat transfer coefficients (i.e. heat transfer rate per unit area per unit temperature) in comparison to a flat receiver. The simulations were first validated against wind tunnel experiments. Convective heat transfer coefficients are reported as a function of receiver orientation (pitch angle), wind speed, wall temperature, blade length to spacing ratio, and blade number. It was shown that the convective heat loss significantly decreases after a characteristic pitch angle of 45°. Furthermore, convective heat loss decreased linearly after a characteristic blade number, which was nine for the investigated configuration. The effect of the blade ratio changed with the receiver orientation, being marginal for shallow pitch angles but becoming significant for angles greater than the characteristic pitch angle of 45°. For example, it was shown that, by increasing the blade number, convective heat losses can be reduced up to ~ 57% even while keeping the same optical properties, which are assumed to be constant for a given bladed aspect ratio and pitch angle.

DOI 10.1063/1.5117571
Citations Scopus - 1
2018 Steer J, Li SW, Morcom N, Jucius S, Ghanadi F, Arjomandi M, 'Pedestrian-level wind conditions around buildings for wind comfort assessment', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018 (2018)

© 2018 Australasian Fluid Mechanics Society. All rights reserved. The practice of investigating the pedestrian level wind environment, so called wind engineering, is now ubiquitou... [more]

© 2018 Australasian Fluid Mechanics Society. All rights reserved. The practice of investigating the pedestrian level wind environment, so called wind engineering, is now ubiquitous. Many city case studies exist in literature but few systematic studies of common urban architectural features exist. Among these common features is the simple channel which is common in large cities and has been well documented in literature as leading to significant wind speed increases. This study investigates the effects of adding a blockage at the channel inlet on observed velocities in the channel centerline on 1:100 scale with a view to applying the results to full scale. Time averaged velocity profiles were used to investigate the effect of blockage size and channel width on wind speed amplification. It was found that counter-intuitively, the size of the blockage at the inlet is not proportional to the size of the peak velocity reduction in the channel. The largest blockage created a minimum flow speed reduction (K = 0.98) for a channel width of 200mm. It was outperformed by the smallest blockage for a channel width of 300mm where a greater speed reduction was observed (K = 1.04). It was found that for buildings nearing the interaction flow regime the addition of a blockage has negligible effect on speed.

2018 Jafari A, Ghanadi F, Emes MJ, Arjomandi M, Cazzolato BS, 'Effect of free-stream turbulence on the drag force on a flat plate', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018 (2018)

© 2018 Australasian Fluid Mechanics Society. All rights reserved. The effect of intensity and length scale of turbulence on the mean and fluctuating drag forces on a flat plate no... [more]

© 2018 Australasian Fluid Mechanics Society. All rights reserved. The effect of intensity and length scale of turbulence on the mean and fluctuating drag forces on a flat plate normal to a boundary layer flow is investigated. Experiments were conducted at the University of Adelaide large wind tunnel to measure the drag force on flat plates of different areas. Two boundary layers of different depths were generated by spires and roughness elements to achieve a range of longitudinal turbulence intensities between 12% and 26% and integral length scales between 0.4 m and 1.22 m. The root-mean-square of the fluctuating drag coefficient was well correlated with a turbulence parameter defined as a function of turbulence intensity (Iu) and integral length scale (Lxu). The results showed that both the fluctuating and the peak drag coefficients increased logarithmically with increasing the turbulence parameter such that increasing the turbulence parameter from 0.11 to 0.47 increased the peak drag coefficient from 1.73 to 3.

Citations Scopus - 1
2018 Torres JF, Ghanadi F, Arjomandi M, Pye J, 'Vortex dynamics within a bladed structure in mixed convection', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018 (2018)

© 2018 Australasian Fluid Mechanics Society. All rights reserved. Mixed convection is generally the dominant form of convective heat transfer in large heated structures at mid- to... [more]

© 2018 Australasian Fluid Mechanics Society. All rights reserved. Mixed convection is generally the dominant form of convective heat transfer in large heated structures at mid- to low temperatures or in small heated structures at high-temperatures, as in solar thermal receivers for concentrating solar power, which is the motivation for the present study. Novel bladed receiver designs have been proposed for reducing thermal emission and improving light trapping. However, convective heat losses from these bladed structures (extended surfaces) may increase compared to non-bladed geometries, which is not desirable as thermal efficiencies may drop. In this study, experiment-validated simulations were used to quantify heat transfer coefficients for a varying blade length and number of blades. The back wall pitch angle ¿ was fixed to 30° and 60° with headwind of 6 m/s and wall temperature of 300°C; the turbulence intensity at the inlet was 1%. A numerical simulation based on the three-dimensional SST k¿¿ turbulence model was performed in OpenFOAM to determine the heat transfer rates and flow behaviour. For a fixed back wall dimension (300 × 300 mm), simulations were conducted for varying the blade number (Nb) while fixing the blade length to spacing ratio to RBS = 1, and varying RBS for Nb = 5. Some interesting vortex dynamics were observed in each case. First, for variable aspect ratio, a transition from a single roll to a two-roll flow between the blade spacing was confirmed at RBS ¿ 1.5 for both pitch angles of ¿ = 30° and 60°. Second, for variable blade number, a transition to a lid-driven-like convection was observed beyond the blade number of Nb = 7, which decreased the heat transfer rate. A larger number of vortices between the blades was responsible for the drop in convective heat transfer coefficient, reaching values even less than the flat case for Nb > 23.

Citations Scopus - 1
2018 Jafari A, Ghanadi F, Emes MJ, Arjomandi M, Cazzolato BS, 'Effect of free-stream turbulence on the drag force on a flat plate', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018 (2018)

© 2018 Australasian Fluid Mechanics Society. All rights reserved. The effect of intensity and length scale of turbulence on the mean and fluctuating drag forces on a flat plate no... [more]

© 2018 Australasian Fluid Mechanics Society. All rights reserved. The effect of intensity and length scale of turbulence on the mean and fluctuating drag forces on a flat plate normal to a boundary layer flow is investigated. Experiments were conducted at the University of Adelaide large wind tunnel to measure the drag force on flat plates of different areas. Two boundary layers of different depths were generated by spires and roughness elements to achieve a range of longitudinal turbulence intensities between 12% and 26% and integral length scales between 0.4 m and 1.22 m. The root-mean-square of the fluctuating drag coefficient was well correlated with a turbulence parameter defined as a function of turbulence intensity (Iu) and integral length scale (Lxu). The results showed that both the fluctuating and the peak drag coefficients increased logarithmically with increasing the turbulence parameter such that increasing the turbulence parameter from 0.11 to 0.47 increased the peak drag coefficient from 1.73 to 3.

Citations Scopus - 1
2018 Torres JF, Ghanadi F, Arjomandi M, Pye J, 'Vortex dynamics within a bladed structure in mixed convection', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018 (2018)

© 2018 Australasian Fluid Mechanics Society. All rights reserved. Mixed convection is generally the dominant form of convective heat transfer in large heated structures at mid- to... [more]

© 2018 Australasian Fluid Mechanics Society. All rights reserved. Mixed convection is generally the dominant form of convective heat transfer in large heated structures at mid- to low temperatures or in small heated structures at high-temperatures, as in solar thermal receivers for concentrating solar power, which is the motivation for the present study. Novel bladed receiver designs have been proposed for reducing thermal emission and improving light trapping. However, convective heat losses from these bladed structures (extended surfaces) may increase compared to non-bladed geometries, which is not desirable as thermal efficiencies may drop. In this study, experiment-validated simulations were used to quantify heat transfer coefficients for a varying blade length and number of blades. The back wall pitch angle ¿ was fixed to 30° and 60° with headwind of 6 m/s and wall temperature of 300°C; the turbulence intensity at the inlet was 1%. A numerical simulation based on the three-dimensional SST k¿¿ turbulence model was performed in OpenFOAM to determine the heat transfer rates and flow behaviour. For a fixed back wall dimension (300 × 300 mm), simulations were conducted for varying the blade number (Nb) while fixing the blade length to spacing ratio to RBS = 1, and varying RBS for Nb = 5. Some interesting vortex dynamics were observed in each case. First, for variable aspect ratio, a transition from a single roll to a two-roll flow between the blade spacing was confirmed at RBS ¿ 1.5 for both pitch angles of ¿ = 30° and 60°. Second, for variable blade number, a transition to a lid-driven-like convection was observed beyond the blade number of Nb = 7, which decreased the heat transfer rate. A larger number of vortices between the blades was responsible for the drop in convective heat transfer coefficient, reaching values even less than the flat case for Nb > 23.

Citations Scopus - 1
2018 Steer J, Li SW, Morcom N, Jucius S, Ghanadi F, Arjomandi M, 'Pedestrian-level wind conditions around buildings for wind comfort assessment', Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018 (2018)

© 2018 Australasian Fluid Mechanics Society. All rights reserved. The practice of investigating the pedestrian level wind environment, so called wind engineering, is now ubiquitou... [more]

© 2018 Australasian Fluid Mechanics Society. All rights reserved. The practice of investigating the pedestrian level wind environment, so called wind engineering, is now ubiquitous. Many city case studies exist in literature but few systematic studies of common urban architectural features exist. Among these common features is the simple channel which is common in large cities and has been well documented in literature as leading to significant wind speed increases. This study investigates the effects of adding a blockage at the channel inlet on observed velocities in the channel centerline on 1:100 scale with a view to applying the results to full scale. Time averaged velocity profiles were used to investigate the effect of blockage size and channel width on wind speed amplification. It was found that counter-intuitively, the size of the blockage at the inlet is not proportional to the size of the peak velocity reduction in the channel. The largest blockage created a minimum flow speed reduction (K = 0.98) for a channel width of 200mm. It was outperformed by the smallest blockage for a channel width of 300mm where a greater speed reduction was observed (K = 1.04). It was found that for buildings nearing the interaction flow regime the addition of a blockage has negligible effect on speed.

2017 Silvestri A, Ghanadi F, Arjomandi M, Cazzolato B, Zander A, 'The effect of the backing cavity on the control of the turbulent boundary layer by the application of a cavity array', 10th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2017 (2017)

The streamwise velocity fluctuations within a fully developed turbulent boundary layer has been investigated downstream of a flushed-surface cavity array underneath a flat plate. ... [more]

The streamwise velocity fluctuations within a fully developed turbulent boundary layer has been investigated downstream of a flushed-surface cavity array underneath a flat plate. The size of the holes in the cavity array were selected to be comparable with the dimensions of the expected coherent structures, based on the friction velocity. This study investigates the effect of the backing cavity volume on attenuation of turbulent energy production within the logarithmic region of the turbulent boundary layer. To this end the turbulence intensity profile and sweep attenuation for three different backing cavity volume have been investigated. All measurements were taken in a closed-loop low turbulence wind tunnel at two different free stream velocities. The results show that when the backing cavity's volume is equal to V+=3×103 the turbulence intensity and sweep intensity are reduced by up to 8% and 7.2% respectively. From this investigation it has been shown that the dampening of sweep events is not solely due to the walls of each individual cavity.

Citations Scopus - 2
2017 Ghanadi F, Emes M, Yu J, Arjomandi M, Kelso R, 'Investigation of the Atmospheric Boundary Layer Characteristics on Gust Factor for the Calculation of Wind Load', INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS (SOLARPACES 2016), Masdar Inst Sci & Technol, Abu Dhabi, U ARAB EMIRATES (2017)
DOI 10.1063/1.4984496
Citations Scopus - 1
2017 Ghanadi F, Yu J, Emes M, Arjomandi M, Kelso R, 'Numerical Investigation of Wind Loads on an Operating Heliostat', INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS (SOLARPACES 2016), Masdar Inst Sci & Technol, Abu Dhabi, U ARAB EMIRATES (2017)
DOI 10.1063/1.4984497
2016 Emes MJ, Ghanadi F, Arjomandi M, Kelso RM, 'An experimental technique for the generation of large-scale spanwise vortices in a wind tunnel', Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016 (2016)

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The presence of large-scale vortices with high spanwise coherence has been observed in the atmospheric boundary l... [more]

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The presence of large-scale vortices with high spanwise coherence has been observed in the atmospheric boundary layer (ABL). This study investigates an innovative technique to generate a large-scale spanwise vortex from the oscillation of a surface-mounted fence in a wind tunnel. Characteristics of the large vortex with a well-defined length scale and its development with downstream distance behind the fence were investigated. Time-averaged profiles of velocity, normal and Reynolds stresses were measured to determine the dominant frequencies of the large vortices in the wake of the oscillating fence. Longitudinal length scales of the spanwise vortices were calculated using the autocorrelation of velocity data. It was found that the size of the largest spanwise vortices are most significantly influenced by the height of the fence, such that the integral length scales increased by 52mm for a 20mm increase in fence height. Spanwise vortices were also found to be 11mm larger when oscillating the fence at the vortex shedding frequency behind a stationary fence. The oscillation amplitude of the fence was found to have a negligible effect on the size of the large spanwise vortices.

2016 Silvestri A, Ghanadi F, Arjomandi M, Cazzolato BS, Zander AC, 'Control of the turbulent boundary layer by the application of a cavity array', Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016 (2016)

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The results presented in this paper provide an insight into the effect of a cavity array on the turbulence produc... [more]

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The results presented in this paper provide an insight into the effect of a cavity array on the turbulence production within a turbulent boundary layer. In the present study, the turbulent energy production within a fully developed turbulent boundary layer has been reduced using a flushed-surface cavity array underneath a flat plate coupled with an acoustic actuator. The size of the holes in the cavity array were selected to be comparable with the dimensions of the expected coherent structures, based on the friction velocity. Experimental measurements were taken in a wind tunnel at a number of locations along the array in the streamwise direction and at a variety of acoustic frequencies generated by the acoustic actuator. A maximum turbulence intensity and sweep intensity reduction of 11% and 10% respectively occurred at Re¿ = 3.771 × 103 in the logarithmic region of the boundary layer when no drive frequency was provided. From this investigation it has been shown that the drive frequency of the acoustic actuator has no effect on the turbulence reduction by the cavity array. Instead the physical parameters of the array, including the number and diameter of the cavities in the array have a much more significant effect.

Citations Scopus - 3
2016 Yu JS, Arjomandi M, Ghanadi F, Kelso R, 'The effect of inclination angle on the flow characteristics of tandem bluff plates', Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016 (2016)

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The flow around bluff bodies in tandem is of significant interest due to its broad range of applications. Past st... [more]

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The flow around bluff bodies in tandem is of significant interest due to its broad range of applications. Past studies have investigated the effect of common geometry configurations such as bluff plates and cylinders and found that flow characteristics varied significantly dependent upon certain geometrical parameters such as bluff body size or spacing ratios. This work explores an unobserved area to determine the effect of inclination angle on the flow around tandem bluff bodies due to an expected change in the pattern of the shed vortices. Specifically, key flow characteristics such as velocity fluctuations and drag are investigated for a pair of flat plates with equal dimensions at a Reynolds number of 54,000. The results are complimented by numerical modelling through computational fluid dynamics using Large Eddy Simulation, where vortex structures are visualized and quantitative drag are validated for. Strouhal number plots show that the inclination angle has a significant effect on the flow interactions between tandem bluff plates, and that when inclined, known transitions between flow regimes no longer occur. The results show that when the shear layer from an upstream bluff body does not meet at the downstream body at any location, a drag reduction is not possible and no optimum gap ratios can be achieved to minimize drag.

Citations Scopus - 2
2016 Silvestri A, Ghanadi F, Arjomandi M, Cazzolato BS, Zander AC, 'Control of the turbulent boundary layer by the application of a cavity array', Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016 (2016)

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The results presented in this paper provide an insight into the effect of a cavity array on the turbulence produc... [more]

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The results presented in this paper provide an insight into the effect of a cavity array on the turbulence production within a turbulent boundary layer. In the present study, the turbulent energy production within a fully developed turbulent boundary layer has been reduced using a flushed-surface cavity array underneath a flat plate coupled with an acoustic actuator. The size of the holes in the cavity array were selected to be comparable with the dimensions of the expected coherent structures, based on the friction velocity. Experimental measurements were taken in a wind tunnel at a number of locations along the array in the streamwise direction and at a variety of acoustic frequencies generated by the acoustic actuator. A maximum turbulence intensity and sweep intensity reduction of 11% and 10% respectively occurred at Re¿ = 3.771 × 103 in the logarithmic region of the boundary layer when no drive frequency was provided. From this investigation it has been shown that the drive frequency of the acoustic actuator has no effect on the turbulence reduction by the cavity array. Instead the physical parameters of the array, including the number and diameter of the cavities in the array have a much more significant effect.

Citations Scopus - 3
2016 Emes MJ, Ghanadi F, Arjomandi M, Kelso RM, 'An experimental technique for the generation of large-scale spanwise vortices in a wind tunnel', Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016 (2016)

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The presence of large-scale vortices with high spanwise coherence has been observed in the atmospheric boundary l... [more]

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The presence of large-scale vortices with high spanwise coherence has been observed in the atmospheric boundary layer (ABL). This study investigates an innovative technique to generate a large-scale spanwise vortex from the oscillation of a surface-mounted fence in a wind tunnel. Characteristics of the large vortex with a well-defined length scale and its development with downstream distance behind the fence were investigated. Time-averaged profiles of velocity, normal and Reynolds stresses were measured to determine the dominant frequencies of the large vortices in the wake of the oscillating fence. Longitudinal length scales of the spanwise vortices were calculated using the autocorrelation of velocity data. It was found that the size of the largest spanwise vortices are most significantly influenced by the height of the fence, such that the integral length scales increased by 52mm for a 20mm increase in fence height. Spanwise vortices were also found to be 11mm larger when oscillating the fence at the vortex shedding frequency behind a stationary fence. The oscillation amplitude of the fence was found to have a negligible effect on the size of the large spanwise vortices.

2016 Yu JS, Arjomandi M, Ghanadi F, Kelso R, 'The effect of inclination angle on the flow characteristics of tandem bluff plates', Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016 (2016)

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The flow around bluff bodies in tandem is of significant interest due to its broad range of applications. Past st... [more]

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The flow around bluff bodies in tandem is of significant interest due to its broad range of applications. Past studies have investigated the effect of common geometry configurations such as bluff plates and cylinders and found that flow characteristics varied significantly dependent upon certain geometrical parameters such as bluff body size or spacing ratios. This work explores an unobserved area to determine the effect of inclination angle on the flow around tandem bluff bodies due to an expected change in the pattern of the shed vortices. Specifically, key flow characteristics such as velocity fluctuations and drag are investigated for a pair of flat plates with equal dimensions at a Reynolds number of 54,000. The results are complimented by numerical modelling through computational fluid dynamics using Large Eddy Simulation, where vortex structures are visualized and quantitative drag are validated for. Strouhal number plots show that the inclination angle has a significant effect on the flow interactions between tandem bluff plates, and that when inclined, known transitions between flow regimes no longer occur. The results show that when the shear layer from an upstream bluff body does not meet at the downstream body at any location, a drag reduction is not possible and no optimum gap ratios can be achieved to minimize drag.

Citations Scopus - 2
2016 Coventry J, Arjomandi M, Barry J, Blanco M, Burgess G, Campbell J, et al., 'Development of the ASTRI Heliostat', SOLARPACES 2015: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, Cape Town, SOUTH AFRICA (2016)
DOI 10.1063/1.4949029
Citations Scopus - 1
2015 Ghanadi F, Arjomandi M, Cazzolato B, Zander A, 'Effectiveness of flow-excited Helmholtz resonator on turbulence structures in streamwise and spanwise directions', 9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015 (2015)

This paper evaluates the capability of a flow-excited cylindrical Helmholtz resonator for the manipulation of the disturbances within a three dimensional turbulent boundary layer ... [more]

This paper evaluates the capability of a flow-excited cylindrical Helmholtz resonator for the manipulation of the disturbances within a three dimensional turbulent boundary layer in the streamwise and spanwise directions. A detailed investigation of the characteristics of the boundary layer downstream of the resonator has been accomplished through an extensive experimental study. The results showed that a reduction in the turbulence intensity of the streamwise velocity fluctuations and sweep events occurs immediately downstream of the resonator but this effect dissipates further away from the resonator orifice. This was hypothesized to be due to thinning of the boundary layer thickness downstream of the resonator in the streamwise direction and weakening of the spanwise vortices generated by the resonator. The results presented in this paper provide an improved understanding for further development of multiple adjacent resonators over an area as a possible alternative system for the purpose of turbulent flow control.

Citations Scopus - 1
2014 Ghanadi F, Arjomandi M, Cazzolato BS, Zander AC, 'Experimental investigation of the application of a self-excited cylindrical Helmholtz resonator for turbulent drag reduction', Proceedings of the 19th Australasian Fluid Mechanics Conference, AFMC 2014 (2014)

An experimental investigation has been undertaken to investigate the suppression of the turbulent events within a boundary layer by different Helmholtz resonators. The flush-mount... [more]

An experimental investigation has been undertaken to investigate the suppression of the turbulent events within a boundary layer by different Helmholtz resonators. The flush-mounted cylindrical resonators were installed within a flat plate and excited by a fully developed turbulent boundary layer. The characteristics of the oncoming boundary layer and the velocity fluctuations in the vicinity of the orifice were measured using hot-wire anemometry. A 12% reduction in turbulent intensity was observed downstream of the resonator for the case when the ratio of the resonator orifice length to the boundary layer thickness was approximately unity. This was accompanied by 5% reduction in sweep intensity. When the diameter and length of the resonator orifice are approximately equal to the thickness of the inner layer, =300, the velocity fluctuations are more positive and spiky resulting in an 11% reduction in sweep intensity. Attenuation of the turbulence production demonstrates the potential of the flow-excited Helmholtz resonator as a novel flow control device.

2012 Ghanadi F, Arjomandi M, Zander AC, Cazzolato BS, 'A review of skin friction drag reduction within the turbulent boundary layer', Advances in Applied Mechanics Research, Conference Proceedings - 7th Australasian Congress on Applied Mechanics, ACAM 2012 (2012)

Skin friction drag reduction in the turbulent boundary layer has high potential benefits which have been a subject of much interest. From general point of view this paper gives an... [more]

Skin friction drag reduction in the turbulent boundary layer has high potential benefits which have been a subject of much interest. From general point of view this paper gives an overview of various methods to control the turbulent boundary layer. Primary section of the paper highlights the importance of skin friction drag reduction in turbulent boundary layers, followed by brief discussion of turbulence and Reynolds shear stress production process in the near wall region. Since there are several ways to suppress the instabilities, which naturally occur in the turbulent boundary layer, lots of control techniques have been investigated in next sections. The present article provides an up-to-date summary of passive and active mechanisms responsible for viscous drag reduction. Furthermore, the implications of previous controller and the success or limitations of various methods are discussed.

2006 Yu JS, Arjomandi M, Ghanadi F, Kelso R, 'The effect of inclination angle on the flow characteristics of tandem bluff plates', Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016 (2006)

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The flow around bluff bodies in tandem is of significant interest due to its broad range of applications. Past st... [more]

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The flow around bluff bodies in tandem is of significant interest due to its broad range of applications. Past studies have investigated the effect of common geometry configurations such as bluff plates and cylinders and found that flow characteristics varied significantly dependent upon certain geometrical parameters such as bluff body size or spacing ratios. This work explores an unobserved area to determine the effect of inclination angle on the flow around tandem bluff bodies due to an expected change in the pattern of the shed vortices. Specifically, key flow characteristics such as velocity fluctuations and drag are investigated for a pair of flat plates with equal dimensions at a Reynolds number of 54,000. The results are complimented by numerical modelling through computational fluid dynamics using Large Eddy Simulation, where vortex structures are visualized and quantitative drag are validated for. Strouhal number plots show that the inclination angle has a significant effect on the flow interactions between tandem bluff plates, and that when inclined, known transitions between flow regimes no longer occur. The results show that when the shear layer from an upstream bluff body does not meet at the downstream body at any location, a drag reduction is not possible and no optimum gap ratios can be achieved to minimize drag.

Citations Scopus - 2
2006 Emes MJ, Ghanadi F, Arjomandi M, Kelso RM, 'An experimental technique for the generation of large-scale spanwise vortices in a wind tunnel', Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016 (2006)

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The presence of large-scale vortices with high spanwise coherence has been observed in the atmospheric boundary l... [more]

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The presence of large-scale vortices with high spanwise coherence has been observed in the atmospheric boundary layer (ABL). This study investigates an innovative technique to generate a large-scale spanwise vortex from the oscillation of a surface-mounted fence in a wind tunnel. Characteristics of the large vortex with a well-defined length scale and its development with downstream distance behind the fence were investigated. Time-averaged profiles of velocity, normal and Reynolds stresses were measured to determine the dominant frequencies of the large vortices in the wake of the oscillating fence. Longitudinal length scales of the spanwise vortices were calculated using the autocorrelation of velocity data. It was found that the size of the largest spanwise vortices are most significantly influenced by the height of the fence, such that the integral length scales increased by 52mm for a 20mm increase in fence height. Spanwise vortices were also found to be 11mm larger when oscillating the fence at the vortex shedding frequency behind a stationary fence. The oscillation amplitude of the fence was found to have a negligible effect on the size of the large spanwise vortices.

2006 Silvestri A, Ghanadi F, Arjomandi M, Cazzolato BS, Zander AC, 'Control of the turbulent boundary layer by the application of a cavity array', Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016 (2006)

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The results presented in this paper provide an insight into the effect of a cavity array on the turbulence produc... [more]

© 2006 Australasian Fluid Mechanics Society. All rights reserved. The results presented in this paper provide an insight into the effect of a cavity array on the turbulence production within a turbulent boundary layer. In the present study, the turbulent energy production within a fully developed turbulent boundary layer has been reduced using a flushed-surface cavity array underneath a flat plate coupled with an acoustic actuator. The size of the holes in the cavity array were selected to be comparable with the dimensions of the expected coherent structures, based on the friction velocity. Experimental measurements were taken in a wind tunnel at a number of locations along the array in the streamwise direction and at a variety of acoustic frequencies generated by the acoustic actuator. A maximum turbulence intensity and sweep intensity reduction of 11% and 10% respectively occurred at Re¿ = 3.771 × 103 in the logarithmic region of the boundary layer when no drive frequency was provided. From this investigation it has been shown that the drive frequency of the acoustic actuator has no effect on the turbulence reduction by the cavity array. Instead the physical parameters of the array, including the number and diameter of the cavities in the array have a much more significant effect.

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Dr Farzin Ghanadi

Position

Research Associate
School of Engineering
Faculty of Engineering and Built Environment

Contact Details

Email farzin.ghanadi@newcastle.edu.au
Phone (02) 4985 4938

Office

Room TA-204
Building TUNRA ANNEXE
Location Callaghan University Drive Callaghan, NSW 2308 Australia
University Drive
Callaghan, NSW 2308
Australia
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