Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-26T07:20:15.795Z Has data issue: false hasContentIssue false

Forced mixing in boundary layers

Published online by Cambridge University Press:  28 March 2006

G. B. Schubauer
Affiliation:
National Bureau of Standards, Washington, D.C.
W. G. Spangenberg
Affiliation:
National Bureau of Standards, Washington, D.C.

Abstract

The effect of increasing the rate of mixing in turbulent boundary layers in a region of adverse pressure gradient has been investigated experimentally. Only the two-dimensional case was considered. The boundary layer was formed on a flat wall in a special wind tunnel in which a variety of adverse pressure gradients could be obtained. Speeds were low enough to justify the neglect of compressibility. The main objective was to compare the effect of increasing the rate of mixing with the effect of reducing the pressure gradient on boundary-layer development and separation. A Variety of mixing schemes was tried, all of them involving fixed devices arranged in a row on the surface in the region of rising pressure. While these differed considerably in effectiveness, they had a generally similar effect on the flow; and, except for effects arising from changes in displacement and momentum thickness introduced at the devices, their effect on the layer was basically equivalent to that of a decrease in pressure gradient. Apart from forced mixing, the shape of the pressure distribution was found to have a significant effect on displacement and momentum thickness, these being minimized and the wall distance decreased for a given pressure rise by a distribution with an initially steep and progressively decreasing gradient.

Type
Research Article
Copyright
© 1960 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Clauser, Francis H. 1954 Turbulent boundary layers in adverse pressure gradients. J. Aero. Sci. 21, 91108.Google Scholar
Clauser, Francis H. 1956 The turbulent boundary layer. Advances in Applied Mechanics, vol. IV, pp. 151. New York: Academic Press Inc.
Coles, Donald 1956 The law of the wake in the turbulent boundary layer. J. Fluid Mech. 1, 191226.Google Scholar
Grose, R. M. 1954 Theoretical and experimental investigation of various types of vortex generators. Rep. United Aircraft Corp. no. R-15362-5.Google Scholar
Kline, Stephen J. 1958 On the nature of stall. Rep. Mech. Eng. Dep. Stanford University, no. MD-4.Google Scholar
McCullough, George B., Nitzberg, Gerald E. & Kelly, John A. 1951 Preliminary investigation of the delay of turbulent flow separation by means of wedge-shaped bodies. NACA Res. Mem. no. A50 L12.Google Scholar
Newman, B. G. 1951 Some contributions to the study of the turbulent boundary layer near separation. Rep. Aust. Dep. Supply no. ACA-53.Google Scholar
Pankhurst, R. C. 1955 Recent British work on methods of boundary-layer control. Proc. of Symposium on Boundary Layer Effects in Aerodynamics, National Physical Laboratory, Paper no. 6.
Robertson, J. M. & Calehuff, G. L. 1957 Turbulence in a diffuser boundary layer. J. of the Hydraul. Div. Amer. Soc. Civil Eng., Paper no. 1393.Google Scholar
Ruetenik, J. R. & Corrsin, S. 1955 Equilibrium turbulent flow in a slightly divergent channel. 50 Jahre Grenzschichtforschung (ed. H. Görtler and W. Tollmien), pp. 44659. Braunschweig: Freidr. Vieweg und Sohn.
Sandborn, Virgil A. & Slogar, Raymond J. 1955 Study of the momentum distribution of turbulent boundary layers in adverse pressure gradients. NACA Tech. Note no. 3264.Google Scholar
Schubauer, G. B. & Klebanoff, P. S. 1951 Investigation of separation of the turbulent boundary layer. Rep. NACA, no. 1030.Google Scholar
Smith, A. M. O. & Murphy, J. S. 1955 A dust method for locating the separation point. J. Aero. Sci. 22, 273.Google Scholar
Stephens, A. V. & Collins, G. H. 1955 Turbulent boundary layer control by ramps or wedges. Rep. Aust. Aero. Res. Comm. no. ACA-55.Google Scholar
Stratford, B. S. 1959 An experimental flow with zero skin friction throughout its region of pressure rise. J. Fluid Mech., 5, 1735.Google Scholar
Taylor, H. D. 1948 Design criteria for and application of the vortex generator mixing principle. Rep. United Aircraft Corp. no. M-15038-1.Google Scholar
Taylor, H. D. 1950 Summary report on vortex generators. Rep. United Aircraft Corp. no. R-05280-9.Google Scholar
Von Doenhoff, Albert E. & Tetervin, Neal 1943 Determination of general relations for the behavior of turbulent boundary layers. Rep. NACA no. 772.Google Scholar
Weiberg, James A. & McCullough, George B. 1952 Wind-tunnel investigation at low speed of a twisted and cambered wing swept back 63° with vortex generators and fences. NACA Res. Mem. no. A 52 A 17.Google Scholar