Skip to main content
SpringerLink
Log in

Roughness Effects on Turbulent Flow Downstream of a Backward Facing Step

  • Published:
Flow, Turbulence and Combustion Aims and scope Submit manuscript

Abstract

This paper investigates the effects of downstream wall roughness on characteristics of separated and reattached turbulent flow downstream of a backward facing step. Detailed particle image velocimetry (PIV) measurements were conducted over rough walls produced from sandpaper 36 and 24 grits and a reference smooth acrylic wall positioned downstream of a backward facing step, one after another. All the experiments were performed at the same Reynolds number of 7050 based on the step height, h and approach mean velocity, ratio of initial boundary layer thickness to step height of 2.2 and expansion ratio of 1.25. The results showed that wall roughness increased the mean reattachment length over the sandpaper 36 and 24 grits by 5 b% and 7 %, respectively, in comparison with the smooth wall value. However, the other mean flow properties within the recirculation region are nearly independent of wall roughness. Beyond 5 step heights from the reattachment point, wall roughness reduced the streamwise mean velocity in the region adjacent to the rough walls. Wall roughness significantly increased the levels of the Reynolds stresses in the recirculation and redevelopment regions. In spite of the higher Reynolds stresses observed over the rough walls compared with the smooth wall, the spatial coherence of turbulence structures embodied in the streamwise and wall-normal auto-correlation function is significantly reduced over the rough walls.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Krogstad, P.-Å, Antonia, R.A.: Surface roughness effects in turbulent boundary layers. Exp. Fluids 27, 450–460 (1999)

    Article  Google Scholar 

  2. Flack, K.A., Schultz, M.P., Shapiro, T.A.: Experimental support for townsend’s reynolds number similarity hypothesis on rough walls. Phys. Fluids 035102, 17 (2005)

    Google Scholar 

  3. Tachie, M.F., Bergstrom, D.J., Balachandar, R.: Rough wall turbulent boundary layers in shallow open channel flow. J. Fluids Eng. 122, 533–541 (2000)

    Article  Google Scholar 

  4. Wu, Y., Christensen, K.T.: Outer-layer similarity in the presence of a practical rough-wall topography. Phys. Fluids 085108, 19 (2007)

    Google Scholar 

  5. Eaton, J.K., Johnston, J.P.: A review of research on subsonic turbulent flow reattachment. AIAA J. 19, 1093–1100 (1981)

    Article  Google Scholar 

  6. Spazzini, P.G., Iuso, G., Onorato, M., Zurlo, N., Di Cicca, G.M.: Unsteady behavior of back-facing step flow. Exp. Fluids 30, 551–561 (2001)

    Article  Google Scholar 

  7. Simpson, R.: Turbulent boundary-layer separation. Annu. Rev. Fluid Mech. 21, 205–234 (1989)

    Article  Google Scholar 

  8. Driver, D.M., Seegmiller, H.L., Marvin, J.G.: Time-dependent behavior of a reattaching shear layer. AIAA J. 25, 914–919 (1987)

    Article  Google Scholar 

  9. Westphal, R. V., Johnston, J.P., Eaton, J.K.: Experimental study of flow reattachment in a single-sided sudden expansion. NASA STI/Recon Tech. Rep. 84, 18571 (1984)

    Google Scholar 

  10. Troutt, T.R., Scheelke, B., Norman, T.R.: Organized structures in a reattaching separated flow field. J. Fluid Mech. 143, 413–427 (1984)

    Article  Google Scholar 

  11. Jovic, S., Driver, D.: Reynolds number effect on the skin friction in separated flows behind a backward-facing step. Exp. Fluids 18, 464–467 (1995)

    Article  Google Scholar 

  12. Narayanan, M.A.B., Khadgi, Y.N., Viswanath, P.R.: Similarities in pressure distribution in separated flow behind backward-facing steps. Aeronaut. Q. 25, 305–312 (1974)

    Google Scholar 

  13. Kuehn, D.: Effects of adverse pressure gradient on the incompressible reattaching flow over a rearward-facing step. AIAA J. 18, 343–344 (1980)

    Article  Google Scholar 

  14. So, R., Lai, Y., Hwang, B., Yoo, G.: Low-Reynolds-number modelling of flows over a backward-facing step. J. Appl. Math. Phys. 39, 13–27 (1988)

    Article  Google Scholar 

  15. Adams, E.W., Johnston, J.P.: Effects of the separating shear layer on the reattachment flow structure. Part 1: pressure and turbulence quantities. Exp. Fluids 6, 400–408 (1988)

    Google Scholar 

  16. Adams, E.W., Johnston, J.P.: Effects of the separating shear layer on the reattachment flow structure. Part 2: reattachment length and wall shear stress. Exp. Fluids 6, 493–499 (1988)

    Google Scholar 

  17. Le, H., Moin, P., Kim, J., Engineering, N.: Direct numerical simulation of turbulent flow over a backward-facing step. J. Fluid Mech. 330, 349–374 (1997)

    Article  MATH  Google Scholar 

  18. Kostas, J., Soria, J., Chong, M.S.: Particle image velocimetry measurements of a backward-facing step flow. Exp. Fluids 33, 838–853 (2002)

    Article  Google Scholar 

  19. Kostas, J., Soria, J., Chong, M.S.: A comparison between snapshot POD analysis of PIV velocity and vorticity data. Exp. Fluids 38, 146–160 (2005)

    Article  Google Scholar 

  20. Kasagi, N., Matsunaga, A.: Three-dimensional particle-tracking velocimetry measurement of turbulence statistics and energy budget in a backward-facing step flow. Int. J. Heat Fluid Flow 16, 477–485 (1995)

    Article  Google Scholar 

  21. Armaly, B., Durst, F., Pereira, J., Schönung, B.: Experimental and theoretical investigation of backward-facing step flow. J. Fluid Mech. 127, 473–496 (1983)

    Article  Google Scholar 

  22. Piirto, M., Saarenrinne, P., Eloranta, H., Karvinen, R.: Measuring turbulence energy with piv in a backward-facing step flow. Exp. Fluids 35, 219–236 (2003)

    Article  Google Scholar 

  23. Scarano, F., Riethmuller, M.L.: Iterative multigrid approach in piv image processing with discrete window offset. Exp. Fluids 26, 513–523 (1999)

    Article  Google Scholar 

  24. Ampadu-Mintah, A.: Surface Roughness Effects on Separated and Reattached Turbulent Flows in Open Channel, MSc. University of Manitoba, Thesis (2013)

    Google Scholar 

  25. Wu, Y., Ren, H., Tang, H.: Turbulent flow over a rough backward-facing step. Int. J. Heat Fluid Flow 44, 155–169 (2013)

    Article  Google Scholar 

  26. Kim, B.N., Chung, M.K.: Experimental study of roughness effects on the separated flow over a backward-facing step. AIAA J. 33, 159–160 (1995)

    Article  Google Scholar 

  27. Driver, D.M., Seegmiller, H.L.: Features of a reattaching turbulent shear layer in divergent channel flow. AIAA J. 23, 163–171 (1985)

    Article  Google Scholar 

  28. Isomoto, K., Honami, S.: The Effect of inlet turbulence intensity on the reattachment process over a backward-facing step. J. Fluids Eng. 111, 87–92 (1989)

    Article  Google Scholar 

  29. Shah, M.K., Agelinchaab, M., Tachie, M.F.: Influence of PIV interrogation area on turbulent statistics up to 4th order moments in smooth and rough wall turbulent flows. Exp. Therm. Fluid Sci. 32, 725–747 (2008)

    Article  Google Scholar 

  30. Essel, E.E.: Experimental Study of Roughness Effect on Turbulent Shear Flow Downstream of a Backward Facing Step, MSc. Thesis, Univerisity of Manitoba (2013)

    Google Scholar 

  31. De Brederode, V., Bradshaw, P.: Three-dimensional flow in nominally two-dimensional separation bubbles: flow behind a rearward-facing step. Imp. Coll. Aeronaut. Rep., 72–19 (1972)

  32. Flack, K.A., Schultz, M.P.: Review of hydraulic roughness scales in the fully rough regime. J. Fluids Eng. 132, 041203–10 (2010)

    Article  Google Scholar 

  33. Prasad, A., Adrian, R., Landreth, C., Offutt, P.: Effect of resolution on the speed and accuracy of particle image velocimetry interrogation. Exp. Fluids 116, 105–116 (1992)

    Article  Google Scholar 

  34. Forliti, D. J., Strykowski, P. J., Debatin, K.: Bias and precision errors of digital particle image velocimetry. Exp. Fluids 28, 436–447 (2000)

    Article  Google Scholar 

  35. Coleman, H., Steele, W.: Engineering application of experimental uncertainty analysis. AIAA J. 33, 1888–1895 (1995)

    Article  Google Scholar 

  36. Spalart, P.: Direct Simulation of a turbulent boundary layer up to Re 𝜃= 1410. J. Fluid Mech. 187, 61–98 (1988)

    Article  MATH  Google Scholar 

  37. Durst, F., Fischer, M., Jovanovic, J., Kikura, H.: Methods to set up and investigate low reynolds number, fully developed turbulent plane channel flows. J. Fluids Eng. 120, 496–503 (1998)

    Article  Google Scholar 

  38. Abe, H., Kawamura, H., Matsuo, Y.: Direct numerical simulation of a fully developed turbulent channel flow with respect to the reynolds number dependence. J. Fluids Eng. 123, 382 (2001)

    Article  Google Scholar 

  39. Eaton, J.K., Johnston, J.P.: Turbulent flow reattachment: an experimental study of the flow and structure behind a backward-facing step, Rept. MD-39. Stanford University (1980)

  40. Jovic, S.: An Experimental Study of a Separated/Reattached Flow Behind a Backward- Facing Step. Re (sub h) = 37, 000. NASA Tech. Memor (1996)

  41. Lu, S.S., Willmarth, W.W.: Measurement of the structure of the reynolds stress in a turbulent boundary layer.pdf. J. Fluid Mech. 60, 481–511 (1973)

    Article  Google Scholar 

  42. Bradshaw, P., Wong, F.: The reattachment and relaxation of a turbulent shear layer. J. Fluid Mech. 52, 113–135 (1972)

    Article  Google Scholar 

  43. Christensen, K.T., Wu, Y.: Characteristics of Vortex Organization in the Outer Layer of Wall Turbulence. Proceedings of Fourth International Symposium on Turbulence and Shear Flow Phenomena, 3, pp 1025–1030. Williamsburg, Virginia (2005)

    Google Scholar 

  44. Nakagawa, S., Hanratty, T.J.: Particle image velocimetry measurements of flow over a wavy wall. Phys. Fluids 13, 3504 (2001)

    Article  Google Scholar 

  45. Volino, R.J., Schultz, M.P., Flack, K.A., States, U., Academy, N., Architecture, N.: Turbulence structure in rough- and smooth-wall boundary layers. J. Fluid Mech. 592, 263–293 (2007)

    Article  MATH  Google Scholar 

  46. Wu, Y., Christensen, K.T.: Spatial structure of a turbulent boundary layer with irregular surface roughness. J. Fluid Mech. 655, 380–418 (2010)

    Article  MATH  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB, R3T 5V6, Canada

    Ebenezer Ekow Essel & Mark Francis Tachie

Authors
  1. Ebenezer Ekow Essel
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Mark Francis Tachie
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Mark Francis Tachie.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Essel, E.E., Tachie, M.F. Roughness Effects on Turbulent Flow Downstream of a Backward Facing Step. Flow Turbulence Combust 94, 125–153 (2015). https://doi.org/10.1007/s10494-014-9549-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10494-014-9549-1

Keywords

Search

Navigation