Abstract
In this commentary, we revisit Raupach’s flow-sheltering paradigm that asserts reduced wall-shear stress behind a surface roughness element (MR Raupach in Boundary-Layer Meteorol, 60(4):375–395, 1992). Direct numerical simulations of a turbulent boundary layer over a wall-mounted rectangular roughness are conducted we consider roughness with three different aspect ratios and flows at two Reynolds numbers. A large computational domain is used to study the behaviours of the wall-shear stress in both the near-wake and the far-wake regions. Aside from a low wall-shear stress region in the near-wake as one would expect from the flow-sheltering paradigm, a high-stress region is found in the far-wake. The presence of such a high-stress region challenges the well-established flow sheltering paradigm and is also counter-intuitive. Detailed analysis of the vortical structures shows that the high wall-shear stress region is a consequence of the horse-shoe-vortex-induced downwash motion in the far-wake.
References
Bose ST, Park GI (2018) Wall-modeled large-eddy simulation for complex turbulent flows. Ann Rev Fluid Mech 50:535–561
Castro IP, Robins AG (1977) The flow around a surface-mounted cube in uniform and turbulent streams. J Fluid Mech 79(2):307–335
Coceal O, Belcher S (2004) A canopy model of mean winds through urban areas. Q J R Meteorol Soc 130(599):1349–1372
Darcy H (1857) Recherches expérimentales relatives au mouvement de l’eau dans les tuyaux. Mallet-Bachelier, France
Eitel-Amor G, Örlü R, Schlatter P (2014) Simulation and validation of a spatially evolving turbulent boundary layer up to Re\(_\theta \)= 8300. Int J Heat Fluid Flow 47:57–69
Flack KA, Schultz MP (2010) Review of hydraulic roughness scales in the fully rough regime. J Fluids Eng 132(4):041–203
Hagen GHL (1854) Über den einfluss der temperatur auf die bewegung des wassers in röhren. Druckerei der Königl. akademie der wissenschaften, Germany
Hearst RJ, Gomit G, Ganapathisubramani B (2016) Effect of turbulence on the wake of a wall-mounted cube. J Fluid Mech 804:513–530
Hussein HJ, Martinuzzi R (1996) Energy balance for turbulent flow around a surface mounted cube placed in a channel. Phys Fluids 8(3):764–780
Hwang HG, Lee JH (2018) Secondary flows in turbulent boundary layers over longitudinal surface roughness. Phys Rev Fluids 3(1):014–608
Jiménez J (2004) Turbulent flows over rough walls. Annu Rev Fluid Mech 36:173–196
Kemler E (1933) A study of the data on the flow of fluids in pipes. Trans ASME 55(2):7–22
Leonardi S, Castro IP (2010) Channel flow over large cube roughness: a direct numerical simulation study. J Fluid Mech 651:519–539
Leonardi S, Orlandi P, Smalley R, Djenidi L, Antonia R (2003) Direct numerical simulations of turbulent channel flow with transverse square bars on one wall. J Fluid Mech 491:229–238
Macdonald R, Griffiths R, Hall D (1998) An improved method for the estimation of surface roughness of obstacle arrays. Atmos Environ 32(11):1857–1864
MacDonald M, Chan L, Chung D, Hutchins N, Ooi A (2016) Turbulent flow over transitionally rough surfaces with varying roughness densities. J Fluid Mech 804:130–161
Martinuzzi R, Tropea C (1993) The flow around surface-mounted, prismatic obstacles placed in a fully developed channel flow. J Fluids Eng 115:85–92
Marusic I, Monty JP, Hultmark M, Smits AJ (2013) On the logarithmic region in wall turbulence. J Fluid Mech 716:R3
Millward-Hopkins JT, Tomlin AS, Ma L, Ingham D, Pourkashanian M (2011) Estimating aerodynamic parameters of urban-like surfaces with heterogeneous building heights. Boundary-Layer Meteorol 141(3):443–465
Moody LF (1944) Friction factors for pipe flow. Trans ASME 66:671–684
Pigott RJS (1933) The flow of fluids in closed conduits. Mech Eng 55(8):497–515
Raupach M (1992) Drag and drag partition on rough surfaces. Boundary-Layer Meteorol 60(4):375–395
Raupach MR, Antonia RA, Rajagopalan S (1991) Rough-wall turbulent boundary layers. Appl Mech Rev 44(1):1–25
Rouhi A, Chung D, Hutchins N (2019) Direct numerical simulation of open-channel flow over smooth-to-rough and rough-to-smooth step changes. J Fluid Mech 866:450–486
Rouse H (1943) Evaluation of boundary roughness. In: Proceedings Second Hydraulics Conference, Univ. of Iowa Studies in Engrg, Bulletin No. 27
Sadique J, Yang XIA, Meneveau C, Mittal R (2017) Aerodynamic properties of rough surfaces with high aspect-ratio roughness elements: effect of aspect ratio and arrangements. Boundary-Layer Meteorol 163(2):203–224
Schultz MP, Kavanagh CJ, Swain GW (1999) Hydrodynamic forces on barnacles: implications on detachment from fouling-release surfaces. Biofouling 13(4):323–335
Shao Y, Yang Y (2005) A scheme for drag partition over rough surfaces. Atmos Environ 39(38):7351–7361
Shao Y, Yang Y (2008) A theory for drag partition over rough surfaces. J Geophys Res Earth 113:F2
Stroh A, Schäfer K, Frohnapfel B, Forooghi P (2020) Rearrangement of secondary flow over spanwise heterogeneous roughness. J Fluid Mech 885:R5
Xie ZT, Castro IP (2008) Efficient generation of inflow conditions for large eddy simulation of street-scale flows. Flow Turbul Combust 81(3):449–470
Yang XIA, Meneveau C (2017) Modelling turbulent boundary layer flow over fractal-like multiscale terrain using large-eddy simulations and analytical tools. Philos Trans R Soc Lond Ser A 375(2091):20160098
Yang Y, Shao Y (2005) Drag partition and its possible implications for dust emission. Water Air Soil Poll 5(3–6):251–259
Yang Y, Shao Y (2006) A scheme for scalar exchange in the urban boundary layer. Boundary-Layer Meteorol 120(1):111–132
Yang XIA, Sadique J, Mittal R, Meneveau C (2016) Exponential roughness layer and analytical model for turbulent boundary layer flow over rectangular-prism roughness elements. J Fluid Mech 789:127–165
Yang XIA, Xu H, Huang XLD, Ge MW (2019) Drag forces on sparsely packed cube arrays. J Fluid Mech 880:992–1019
Acknowledgements
This material is based upon work supported by the Department of Energy under Award Number(s) DE-FE0031280. Disclaimer: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favouring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. The DNSs are performed on XSEDE and ACI-ICS. MG thanks the support of National Natural Science Foundation of China (No. 11772128).
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Yang, X., Ge, M. Revisiting Raupach’s Flow-Sheltering Paradigm. Boundary-Layer Meteorol 179, 313–323 (2021). https://doi.org/10.1007/s10546-020-00597-8
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DOI: https://doi.org/10.1007/s10546-020-00597-8