2015 | Kamruzzaman M, Djenidi L, Antonia RA, Talluru KM, 'Scale-by-scale energy budget in a turbulent boundary layer over a rough wall', International Journal of Heat and Fluid Flow, (2015)Hot-wire velocity measurements are carried out in a turbulent boundary layer over a rough wall consisting of transverse circular rods, with a ratio of 8 between the spacing (w) of two consecutive rods and the rod height (k). The pressure distribution around the roughness element is used to accurately measure the mean friction velocity (Ut) and the error in the origin. It is found that Ut remained practically constant in the streamwise direction suggesting that the boundary layer over this surface is evolving in a self-similar manner. This is further corroborated by the similarity observed at all scales of motion, in the region 0.2=y/d=0.6, as reflected in the constancy of Reynolds number (RÂ¿) based on Taylor's microscale and the collapse of Kolmogorov normalized velocity spectra at all wavenumbers.A scale-by-scale budget for the second-order structure function <(du)2> (du=u(x+r)-u(x), where u is the fluctuating streamwise velocity component and r is the longitudinal separation) is carried out to investigate the energy distribution amongst different scales in the boundary layer. It is found that while the small scales are controlled by the viscosity, intermediate scales over which the transfer of energy (or <(du)3>) is important are affected by mechanisms induced by the large-scale inhomogeneities in the flow, such as production, advection and turbulent diffusion. For example, there are non-negligible contributions from the large-scale inhomogeneity to the budget at scales of the order of Â¿, the Taylor microscale, in the region of the boundary layer extending from y/d=0.2 to 0.6 (d is the boundary layer thickness). | | |
2015 | Djenidi L, Antonia RA, 'A general self-preservation analysis for decaying homogeneous isotropic turbulence', Journal of Fluid Mechanics, 773 345-365 (2015)A general framework of self-preservation (SP) is established, based on the transport equation of the second-order longitudinal velocity structure function in decaying homogeneous isotropic turbulence (HIT). The analysis introduces the skewness of the longitudinal velocity increment, S(r, t) (r and t are space increment and time), as an SP controlling parameter. The present SP framework allows a critical appraisal of the specific assumptions that have been made in previous SP analyses. It is shown that SP is achieved when S(r, t) varies in a self-similar manner, i.e. S=c(t)f(r/l) where l is a scaling length, and c(t) and f(r/l) are dimensionless functions of time and (r/l), respectively. When c(t) is constant, l can be identified with the Kolmogorov length scale Â¿, even when the Reynolds number is relatively small. On the other hand, the Taylor microscale Â¿ is a relevant SP length scale only when certain conditions are met. The decay law for the turbulent kinetic energy (k) ensuing from the present SP is a generalization of the existing laws and can be expressed as k ~ (t-t0)^{n}+B, where B is a constant representing the energy of the motions whose scales are excluded from the SP range of scales. When B = 0, SP is achieved at all scales of motion and Â¿ becomes a relevant scaling length together with Â¿. The analysis underlines the relation between the initial conditions and the power-law exponent n and also provides a link between them. In particular, an expression relating n to the initial values of the scaling length and velocity is developed. Finally, the present SP analysis is consistent with both experimental grid turbulence data and the eddy-damped quasi-normal Markovian numerical simulation of decaying HIT by Meldi & Sagaut (J. Turbul., vol. 14, 2013, pp. 24-53). | | |
2015 | Kamruzzaman M, Djenidi L, Antonia RA, Talluru KM, 'Drag of a turbulent boundary layer with transverse 2D circular rods on the wall', EXPERIMENTS IN FLUIDS, 56 (2015) | | |
2014 | Djenidi L, Antonia RA, 'Transport equation for the mean turbulent energy dissipation rate in low-R-lambda grid turbulence', JOURNAL OF FLUID MECHANICS, 747 288-315 (2014) [C1] | | |
2014 | Thiesset F, Antonia RA, Djenidi L, 'Consequences of self-preservation on the axis of a turbulent round jet', JOURNAL OF FLUID MECHANICS, 748 (2014) [C1] | | |
2014 | Lee S-K, Djenidi L, Antonia RA, 'Empirical correlations for slightly heated decaying passive-grid turbulence', Heat Transfer Engineering, 35 1482-1490 (2014) [C1]For homogeneous isotropic turbulence approximated by grid turbulence, velocity and temperature fluctuations decay under the effects of viscosity and thermal diffusivity of the fluid. In the self-similar region of grid flow, there is no mean shear and no turbulence production, and the decay rate is well represented by a power law; this is supported by the present measurements in three different grid flows and by previously published data for passive-grid turbulence obtained over different ranges of streamwise distance and/or Reynolds number. The grid flow is slightly heated so that temperature acts as a passive scalar. From dimensional analysis and empirical power-law correlations, relations for basic flow parameters, such as the Kolmogorov, Taylor, and Corrsin microscales, and the Reynolds and PÃ©clet numbers, are established as functions of the normalized streamwise distance downstream of the grid. With these relations, it is possible to determine the flow parameters for a specific passive-grid geometry or, more generally, a specific set of initial conditions. Â© 2014 Copyright Taylor & Francis Group, LLC. | | |
2014 | Djenidi L, Antonia RA, Amielh M, Anselmet F, 'Use of PIV to highlight possible errors in hot-wire Reynolds stress data over a 2D rough wall', EXPERIMENTS IN FLUIDS, 55 (2014) [C1] | | |
2014 | Antonia RA, Djenidi L, Danaila L, 'Collapse of the turbulent dissipative range on Kolmogorov scales', PHYSICS OF FLUIDS, 26 (2014) [C1] | | |
2014 | Thiesset F, Schaeffer V, Djenidi L, Antonia RA, 'On self-preservation and log-similarity in a slightly heated axisymmetric mixing layer', PHYSICS OF FLUIDS, 26 (2014) [C1] | | |
2014 | Lefeuvre N, Thiesset F, Djenidi L, Antonia RA, 'Statistics of the turbulent kinetic energy dissipation rate and its surrogates in a square cylinder wake flow', Physics of Fluids, 26 (2014) [C1]A numerical simulation based on the lattice Boltzmann method is carried out in the wake of a square cylinder with the view to investigating possible surrogates for the instantaneous turbulent kinetic energy dissipation rate, Ie{cyrillic, ukrainian}, as well as its mean value, \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }$\end{document}Ie{cyrillic, ukrainian}. Various surrogate approximations of Ie{cyrillic, ukrainian}, based on local isotropy (Ie{cyrillic, ukrainian}iso), local axisymmetry along the streamwise direction x (Ie{cyrillic, ukrainian}a, x) and the transverse direction y (Ie{cyrillic, ukrainian}a, y), local homogeneity (Ie{cyrillic,ukrainian}hom), and homogeneity in the transverse plane, (Ie{cyrillic,ukrainian}4x), are assessed. All the approximations are in agreement with \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }$\end{document}Ie{cyrillic,ukrainian}when the distance downstream of the obstacle is larger than about 40 diameters. Closer to the obstacle, the agreement remains reasonable only for \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }_{a,x}$\end{document}Ie{cyrillic, ukrainian}a,x, \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }{hom}$\end{document}?hom and \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }{4x}$\end{document}Ie{cyrillic, ukrainian}4x. The probability density functions (PDF) and joint PDFs of Ie{cyrillic, ukrainian} and its surrogates show that Ie{cyrillic, ukrainian}4x correlates best withIe{cyrillic, ukrainian}while ?iso and Ie{cyrillic, ukrainian}hom present the smallest correlation. The results indicate that Ie{cyrillic, ukrainian}4x is a very good surrogate for Ie{cyrillic, ukrainian}and can be used for correctly determining the behaviour of Ie{cyrillic, ukrainian}. | | |
2014 | Djenidi L, Tardu SF, Antonia RA, Danaila L, 'Breakdown of Kolmogorov's first similarity hypothesis in grid turbulence', JOURNAL OF TURBULENCE, 15 596-610 (2014) [C1] | | |
2013 | Antonia RA, Lee SK, Djenidi L, Lavoie P, Danaila L, 'Invariants for slightly heated decaying grid turbulence', JOURNAL OF FLUID MECHANICS, 727 379-406 (2013) [C1] | | |
2013 | Rajagopalan S, Antonia RA, Djenidi L, 'Effect of mesh grids on the turbulent mixing layer of an axisymmetric jet', Heat Transfer Engineering, 34 1216-1225 (2013) [C1]This article focuses on the effect that two different mesh grids have on the structure of the mixing layer of an axisymmetric jet. Detailed measurements of mean velocity and turbulent velocity fluctuations are made with an X hot-wire probe in the range 0.5 = x/d = 10, where x is the longitudinal distance from the nozzle exit plane and d is the nozzle diameter. The grids are introduced at two locations-one location just downstream of the nozzle exit plane and the other location upstream of the nozzle exit plane in order to perturb the nozzle exit boundary layer. One mesh completely covers the nozzle (full mesh or FM) and the other mesh covers the central, high-speed zone (disk mesh or DM). With reference to the undisturbed jet, FM yields a significant reduction in the turbulence intensity and width of the shear layer, whereas DM enhances the turbulence intensity and increases the width of the shear layer. Both grids suppress the formation of the Kelvin-Helmholtz instability in the mixing layer. Results are presented, mainly at x/d = 5 and 6 in both the spectral domain and physical space. In the latter context, second-and third-order structure functions associated with u (the longitudinal velocity fluctuation) and v (the lateral or radial velocity fluctuation) are presented only for the flow perturbed by placing the mesh outside the nozzle. All mesh geometries have a more significant effect on the second-order structure function of u than on that of v. The third-order energy transfer term is affected in such a way that, relative to the undisturbed jet, its peak location is shifted to a smaller scale when FM is used and to a larger scale with DM. This is consistent with our observations that FM reduces the turbulence in the shear layer while DM enhances it. It is suggested that the large-scale vortices that are formed at the edge of the grids play a significant role in the transfer of energy. Â© 2013 Taylor & Francis Group, LLC. | | |
2013 | Djenidi L, Tardu SF, Antonia RA, 'Relationship between temporal and spatial averages in grid turbulence', Journal of Fluid Mechanics, 730 593-606 (2013) [C1] | | |
2013 | Thiesset F, Antonia RA, Danaila L, Djenidi L, 'Karman-Howarth closure equation on the basis of a universal eddy viscosity', PHYSICAL REVIEW E, 88 (2013) [C1] | | |
2013 | Kamruzzaman M, Wahiduzzaman M, Alam MM, Djenidi L, 'The effects of magnetic field on the fluid flow through a rotating straight duct with large aspect ratio', Procedia Engineering, 56 239-244 (2013) [C1]This paper presents a numerical study of an investigation of a fluid flow through a rotating rectangular straight duct in the presence of magnetic field. The straight duct of rectangular cross-section rotates at a constant angular velocity about the centre of the duct cross-section is same as the axis of the magnetic field along the positive direction in the stream wise direction of the flows. Numerical calculation is based on the Magneto hydrodynamics incompressible viscous steady fluid model whereas Spectral method is applied as a main tool. Flow depends on the Magnetic parameter, Dean number and Taylor number. One of the interesting phenomena of the fluid flow is the solution curve and the flow structures in case of rotation of the duct axis. The calculation are carried out for 5 = Mg = 50000, 50 = Tr 100000, Dn 500, 1000, 1500 and 2000 where the aspect ratio Â¿ 3.0. The maximum axial flow will be shifted to the centre from the wall and turn into the ring shape under the effects of high magnetic parameter and large Taylor number whereas the fluid particles strength is weak. Â© 2013 The Authors. Published by Elsevier Ltd. | | |
2012 | Djenidi L, Tardu SF, 'On the anisotropy of a low-Reynolds-number grid turbulence', Journal of Fluid Mechanics, 702 332-353 (2012) [C1] | | |
2012 | Djenidi L, Antonia RA, 'A spectral chart method for estimating the mean turbulent kinetic energy dissipation rate', Experiments in Fluids, 53 1005-1013 (2012) [C1] | | |
2012 | Lee S-K, Benaissa A, Djenidi L, Lavoie P, Antonia RA, 'Decay of passive-scalar fluctuations in slightly stretched grid turbulence', Experiments in Fluids, 53 909-923 (2012) [C1] | | |
2012 | Lee SK, Benaissa A, Djenidi L, Lavoie P, Antonia RA, 'Scaling range of velocity and passive scalar spectra in grid turbulence (vol 24, 075101, 2012)', PHYSICS OF FLUIDS, 24 (2012) [C3] | | |
2012 | Lee S-K, Benaissa A, Djenidi L, Lavoie P, Antonia RA, 'Scaling range of velocity and passive scalar spectra in grid turbulence', Physics of Fluids, 24 075101 (2012) [C1] | | |
2011 | Lefeuvre N, Djenidi L, Tardu S, 'Momentum and scalar transport in a localised synthetic turbulence in a channel flow with a short contraction', Journal of Physics: Conference Series, 318 052047 (2011) [C1] | | |
2010 | Djenidi L, Antonia R, Amielh M, Anselmet F, 'POD analysis of the near-wall region of a rough wall turbulent boundary layer', IUTAM Bookseries, 22 49-54 (2010)A proper orthogonal decomposition (POD) analysis is carried out with particle image velocity (PIV) measurements of a turbulent boundary layer over a rough wall made of transverse square bars. Two bar spacings were investigated (w/k = 3 and 7, w is the bar spacing and k the bar diameter). This ratio affects the energy distribution amongst the POD modes throughout the boundary layer, the higher modes, i.e. the relatively small-scale and less energetic motions, being the most perturbed. The first few near-wall POD modes were also affected by the spacing. Â© Springer Science+Business Media B.V. 2010. | | |
2010 | Agrawal A, Djenidi L, Antonia RA, 'Near-field measurements and development of a new boundary layer over a flat plate with localized suction', Experiments in Fluids, 48 747-762 (2010) [C1] | | |
2010 | Antonia RA, Lavoie P, Djenidi L, Benaissa A, 'Effect of a small axisymmetric contraction on grid turbulence', Experiments in Fluids, 49 3-10 (2010) [C1] | | |
2009 | Djenidi L, Antonia RA, 'Momentum and heat transport in a three-dimensional transitional wake of a heated square cylinder', Journal of Fluid Mechanics, 640 109-129 (2009) [C1] | | |
2009 | Agrawal A, Djenidi L, Agrawal A, 'Simulation of gas flow in microchannels with a single 90 degrees bend', Computers & Fluids, 38 1629-1637 (2009) [C1] | | |
2009 | Djenidi L, Agrawal A, Antonia RA, 'Anisotropy measurements in the boundary layer over a flat plate with suction', Experimental Thermal and Fluid Science, 33 1106-1111 (2009) [C1] | | |
2008 | Djenidi L, 'Structure of a turbulent crossbar near-wake studied by means of lattice Boltzmann simulation', Physical Review E, 77 (2008) [C1] | | |
2008 | Oyewola O, Djenidi L, Antonia RA, 'Response of mean turbulent energy dissipation rate and spectra to concentrated wall suction', Experiments in Fluids, 44 159-165 (2008) [C1] | | |
2008 | Djenidi L, Antonia RA, Amielh M, Anselmet F, 'A turbulent boundary layer over a two-dimensional rough wall', Experiments in Fluids, 44 37-47 (2008) [C1] | | |
2007 | Oyewola O, Djenidi L, Antonia RA, 'Influence of localised double suction on a turbulent boundary layer', Journal of Fluids and Structures, 23 787-798 (2007) [C1] | | |
2007 | Oyewola MO, Djenidi L, Antonia RA, 'Examination of anisotropy of the small-scale motion in a perturbed low Reynolds number turbulent boundary layer', Experimental Thermal and Fluid Science, 32 309-315 (2007) [C1] | | |
2007 | Benaissa A, Djenidi L, Antonia RA, Parker R, 'Effect of initial conditions on the scalar decay in grid turbulence at low R Â¿', Proceedings of the 16th Australasian Fluid Mechanics Conference, 16AFMC, 914-918 (2007)Decaying grid turbulence is considered at low Reynolds number (R Â¿~ 50) for different initial conditions. Three different grid geometries are used. Heat is injected via a mandoline at a distance of 1.5 M from the grid. The amount of heating is such that temperature may be treated as a passive scalar. A small contraction (1.36:1) is added at a distance of 11M downstream of the grid. The power-law exponents for the scalar variance are compared with those for the turbulent kinetic energy. These exponents depend on the grid geometry. For the isotropic dissipation rate (Chi;) iso, the power-law exponent agrees with that inferred from the temperature variance transport equation. Restricting the range of validity of the decay law affects the magnitudes of the origin and decay exponent. Secondorder temperature structure functions collapse when the normalization is based on the local temperature variance and the Corrsin microscale but the asymptotic form of this collapse depends on the initial conditions. | | |
2007 | Lavoie PLD, Djenidi L, Antonia RA, 'Effects of initial conditions in decaying turbulence generated by passive grids', Journal of Fluid Mechanics, 585 395-420 (2007) [C1] | | |
2006 | Djenidi L, 'Lattice-Boltzmann simulation of grid-generated turbulence', Journal of Fluid Mechanics, 552 13-35 (2006) [C1] | | |
2006 | Djenidi L, Moghtaderi B, 'Numerical investigation of laminar mixing in a coaxial microreactor', Journal of Fluid Mechanics, 568 223-242 (2006) [C1] | | |
2006 | Agrawal A, Djenidi L, Antonia RA, 'Investigation of flow around a pair of side-by-side square cylinders using the lattice Boltzmann method', Computers and Fluids, 35 1093-1107 (2006) [C1] | | |
2006 | Moghtaderi B, Shames I, Djenidi L, 'Microfluidic characteristics of a multi-holed baffle plate micro-reactor', International Journal of Heat and Fluid Flow, 27 1069-1077 (2006) [C1] | | |
2006 | Leonardi S, Orlandi P, Djenidi L, Antonia RA, 'Guidelines for modeling a 2D rough wall channel flow', Flow Turbulence and Combustion, 77 41-57 (2006) [C1] | | |
2006 | Burattini P, Lavoie PLD, Agrawal A, Djenidi L, Antonia RA, 'Power law of decaying homogeneous isotropic turbulence at low Reynolds number', Physical Review E, 73 (2006) [C1] | | |
2005 | Oyewola O, Djenidi L, Antonia RA, 'Spanwise vorticity measurements in a perturbed boundary layer', Experiments in Fluids, 39 152-155 (2005) [C1] | | |
2005 | Lavoie PLD, Burattini P, Djenidi L, Antonia RA, 'Effect of initial conditions on decaying grid turbulence at low R-gimel', Experiments in Fluids, 39 865-874 (2005) [C1] | | |
2005 | Agrawal A, Djenidi L, Antonia RA, 'Simulation of gas flow in microchannels with a sudden expansion or contraction', Journal of Fluid Mechanics, 530 135-144 (2005) [C1] | | |
2004 | Oyewola O, Djenidi L, Antonia RA, 'The response of a turbulent boundary layer to concentrated suction applied through a pair of porous wall strips', Journal of Fluids Engineereing, 126 888-890 (2004) [C1] | | |
2004 | Leonardi S, Orlandi P, Djenidi L, Antonia RA, 'Structure of turbulent channel flow with square bars on one wall', International Journal of Heat and Fluid Flow, 25 384-392 (2004) [C1] | | |
2004 | Oyewola O, Djenidi L, Antonia RA, 'Influence of localised wall suction on the anisotropy of the Reynolds stress tensor in a turbulent boundary layer', Experiments in Fluids, 37 187-193 (2004) [C1] | | |
2004 | Agrawal A, Djenidi L, Antonia RA, 'LIF based detection of low-speed streaks', experiments in fluids, 36 600-603 (2004) [C1] | | |
2004 | Burattini P, Djenidi L, 'Velocity and passive scalar characteristics in a round jet with grids at the nozzle exit', Flow, Turbulence and Combustion, 72 199-218 (2004) [C1] | | |
2003 | Djenidi L, Antonia RA, Savill AM, 'A numerical study of drag reduction by mini-belts in a smooth wall turbulent boundary layer', The Aeronautical Journal, Paper No.2728 (2003) [C1] | | |
2003 | Leonardi S, Orlandi P, Smalley RJ, Djenidi L, Antonia RA, 'Direct numerical simulations of turbulent channel flow with transverse square bars on one wall', Journal of Fluid Mechanics, 491 229-238 (2003) [C1] | | |
2003 | Oyewola O, Djenidi L, Antonia RA, 'Combined influence of the Reynolds number and localised wall suction on a turbulent boundary layer', Experiments in Fluids, 35 199-206 (2003) [C1] | | |
2002 | Smalley RJ, Leonardi S, Antonia RA, Djenidi L, Orlandi P, 'Reynolds stress anistropy of turbulent rough wall layers', Experiments in Fluids, 33 31-37 (2002) [C1] | | |
2001 | Djenidi L, Antonia RA, 'Calculation of the effect of concentrated wall suction on a turbulent boundary layer using a second-order moment closure', International Journal of Heat and Fluid Flow, 22 487-494 (2001) [C1] | | |
2001 | Rehab H, Antonia RA, Djenidi L, 'Steamwise evloution of a high-Schmidt-number passive scalar in a turbulent plane wake', Experiments in Fluids, 31 186-192 (2001) [C1] | | |
2001 | Smalley RJ, Antonia RA, Djenidi L, 'Self-preservation of rough-wall turbulent boundary layers', European Journal of Mechanics B-Fluids, 20 591-602 (2001) [C1] | | |
2000 | Rehab H, Antonia RA, Djenidi L, Mi J, 'Characteristics of fluorescein dye and temperature fluctuations in a turbulent near-wake', Experiments in Fluids, 28 462-470 (2000) [C1] | | |
1999 | Djenidi L, Elavarasan R, Antonia RA, 'The Turbulent Boundary Layer Over Transverse Square Cavities', Journal of Fluid Mechanics, 395 271-294 (1999) [C1] | | |
1998 | Djenidi L, Antonia RA, Hundseid J, Krogstad PA, 'Combined Effect of Wall Suction and Riblets on a Low R Turbulent Boundary Layer', The Aeronautical Journal, 102 53-57 (1998) [C1] | | |
1997 | Antonia RA, Djenidi L, 'Reynolds stress producing motions in smooth and rough wall boundary layers', Advances in Fluid Mechanics, 15 181-199 (1997)Motions that are responsible for the production and maintenance of the Reynolds shear stress in a turbulent boundary layer may be affected by the Reynolds number and the surface roughness. Evidence for each of these effects is presented, based mainly on experiments carried out in our laboratory. The effects are felt in both inner and outer regions of the layer. The evidence points to the non-universality of the active motion and to the sensitivity of the large scale motion to boundary conditions. | | |
1997 | Djenidi L, Antonia RA, 'Modeling of the Reynolds stress transport equation', AIAA JOURNAL, 35 450-455 (1997) | | |
1997 | Dubief Y, Djenidi L, Antonia RA, 'The measurement of partial derivative u/partial derivative y in a turbulent boundary layer over a riblet surface', INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW, 18 183-187 (1997) | | |
1997 | Dubief Y, Djenidi L, Antonia RA, 'The measurement of Â¿u/Â¿y in a turbulent boundary layer over a riblet surface', International Journal of Heat and Fluid Flow, 18 183-187 (1997)Statistics of Â¿u/Â¿y have been measured in a turbulent boundary layer over either a smooth wall or a riblet surface using parallel hot wires. Over the riblets, the mean square value of Â¿u/Â¿y (normalised with smooth wall variables) is smaller than over the smooth wall; the difference increases as the distance to the wall decreases. Also this difference is larger when the riblets operate in a drag-augmenting mode. These changes would reflect changes in the near-wall turbulence structure. Furthermore, on the basis that Â¿u/Â¿y is a major contributor to the spanwise vorticity, the results indicate that, relative to the smooth wall, the mean square spanwise vorticity is reduced near a riblet surface. Â© 1997 by Elsevier Science Inc. | | |
1997 | Djenidi L, Dubief Y, Antonia RA, 'Advantages of using a power law in a low R(theta) turbulent boundary layer', EXPERIMENTS IN FLUIDS, 22 348-350 (1997) | | |
1996 | Djenidi L, Antonia RA, 'Laser Doppler anemometer measurements of turbulent boundary layer over a riblet surface', AIAA JOURNAL, 34 1007-1012 (1996) | | |
1995 | CHING CY, DJENIDI L, ANTONIA RA, 'LOW-REYNOLDS-NUMBER EFFECTS IN A TURBULENT BOUNDARY-LAYER', EXPERIMENTS IN FLUIDS, 19 61-68 (1995) | | |
1994 | DJENIDI L, ANSELMET F, ANTONIA RA, 'LDA MEASUREMENTS IN A TURBULENT BOUNDARY-LAYER OVER A D-TYPE ROUGH WALL', EXPERIMENTS IN FLUIDS, 16 323-329 (1994) | | |
1994 | ANTONIA RA, DJENIDI L, SPALART PR, 'ANISOTROPY OF THE DISPERSION TENSOR IN A TURBULENT BOUNDARY-LAYER', PHYSICS OF FLUIDS, 6 2475-2479 (1994) | | |
1994 | Djenidi L, Anselmet F, Liandrat J, Fulachier L, 'Laminar boundary layer over riblets', Physics of Fluids, 6 2993-2999 (1994)Laser doppler anemometry (LDA) measurements and numerical calculations have been made for a laminar boundary layer on triangular riblets. Calculated mean velocity distributions along the riblet contour are in good agreement with the measured ones. The results show that no transversal motion exists above and within the riblet valleys (e.g., no secondary motion). It is found that despite the large wetted area increase, the frictional drag is not increased on riblets relative to a smooth wall. This result suggests that the viscous effects are at play in the drag reduction for a turbulent boundary layer, in the sense that they compensate for the increase in wetted area. Â© 1994 American Institute of Physics. | | |
1993 | DJENIDI L, ANTONIA RA, 'LDA MEASUREMENTS IN LOW REYNOLDS-NUMBER TURBULENT BOUNDARY-LAYER', EXPERIMENTS IN FLUIDS, 14 280-288 (1993) | | |