Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2025-01-04T04:22:08.044Z Has data issue: false hasContentIssue false
  • English
  • Français

Boundary-layer development on the afterbody of an engine nacelle

Published online by Cambridge University Press:  20 April 2006

Eugene Lai  and
L. C. Squire
Eugene Lai
Affiliation:
Cambridge University Engineering Department
L. C. Squire
Affiliation:
Cambridge University Engineering Department
Get access Rights & Permissions [Opens in a new window]

Abstract

Measurements have been made of the pressure distribution and turbulent-boundary-layer development on the afterbody of a model engine nacelle with a jet exhausting from the base and with the jet replaced by a parallel solid sting. It was found that the effect of replacing the jet by a solid body was to increase the pressure recovery over the afterbody and hence give a lower drag than with the jet. These changes in the pressure distribution affected the boundary-layer development and turbulence structure by different methods based on a momentum integral equation and the kinetic equation for the turbulence. Both methods approximately incorporate the effects of convergence and divergence of the flow caused by changes in transverse curvature of the surface. Neither method was completely satisfactory for the prediction of the overall boundary-layer development.

It was also found that, near the tail of the model, where the body radius is decreasing rapidly, the Reynolds shear stress was much lower than it would be in a two-dimensional boundary layer with the same pressure gradient. Calculations and analysis based on earlier work show that this reduction is directly related to the rates of strain associated with the convergence of the streamlines over the afterbody.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 158 , September 1985 , pp. 23 - 46
Copyright
© 1985 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

Abeyounis, W. K. & Putnam L. E. 1980 Investigation of the flow field surrounding circular-are boat-tail nozzles at subsonic speeds. NASA TP-1633.
Bradshaw P. 1966 The turbulent structure of equilibrium layers. NPL Aero. Rep. 1184.Google Scholar
Bradshaw P. 1971 Introduction to Turbulence and its Measurements. Pergamon.
Bradshaw, P. & Unsworth K. 1974 An improved Fortran program for the Bradshaw-Ferris-Atwell method of calculating turbulent shear layers. Imperial College Aero. Rep. 74–02.Google Scholar
Cebeci T. 1970 Laminar and turbulent incompressible boundary layers on slender bodies of revolution in axial flow. Trans. ASME D: J. Basic Engng 92, 545–550.Google Scholar
Chase D. M. 1972 Mean velocity profile of a thick turbulent boundary layer along a circular cylinder. AIAA J. 10, 849–850Google Scholar
Durst F., Launder B. E., Schmidt, F. W. & Whitelaw, J. H. (eds) 1979 Turbulent Shear Flows I. Springer.
Galbraith R. A. Mcd. 1976 Contributions to the analysis and prediction of turbulent boundary layers. Ph.D. Dissertation, University of Cambridge.
Galbraith, R. A. Mcd. & Head M. R. 1975 Eddy viscosity and mixing length from measured boundary layer developments. Aero Quart. 26, 133–154.Google Scholar
Green J. E., Weeks, D. J. & Brooman J. W. F. 1973 Prediction of turbulent boundary layers and wakes in compressible flow by a lag-entrainment method. Aero. Res. Counc. R & M 3791.Google Scholar
Head M. R. 1976 Eddy viscosity in turbulent boundary layers. Aero Quart. 27, 270–275.Google Scholar
Head, M. R. & Galbraith R. A. McD. 1975 Eddy viscosity and entrainment in equilibrium boundary layers Aero Quart. 26, 229–242.Google Scholar
Head, M. R. & Patel V. C. 1970 Improved entrainment method for calculating turbulent boundary layer development. Aero. Res. Counc. R & M 3643.Google Scholar
Hess, J. L. & Martin R. P. 1974 Improved solution for potential flow about arbitrary axisymmetric bodies by the use of a higher-order surface source method. Part I. Theory and results. NASA CR-134694.
Lai E. 1983 Boundary layer development on nacelle afterbodies. Ph.D. Dissertation, University of Cambridge.
Ludwieg, H. & Tillmann W. 1949 Untersuchungen über die Wandschubspannung in turbulenten Reibungsschichten. English translation, Investigation of the wall-shearing stress in turbulent layers, is available as NACA TM-1285.
Patel, V. C. & Lee Y. T. 1977 Thick axisymmetric turbulent boundary layer and near wake of a low-drag body of revolution. IIHR Rep. No. 210, University of Iowa.Google Scholar
Patel V. C, Lee, Y. T. & Güven O. 1979 Measurements in the thick axisymmetric turbulent boundary layer and the near wake of a low-drag body of revolution. In Turbulent Shear Flows I (ed. F. Durst, B. E. Launder, F. W. Schmidt & J. H. Whitelaw), pp. 137–153. Springer.
Patel V. C., Nakayama, A. & Damian R. 1974 Measurements in the thick axisymmetric turbulent boundary layer near the tail of a body of revolution. J. Fluid Mech. 63, 345–367.Google Scholar
Putnam L. E., Abeyounis W. K. 1976 Experimental and theoretical study of flow fields surrounding boat-tail nozzles at subsonic speeds. AIAA Paper No. 76–675.Google Scholar
Reubush D. E. 1974 Experimental study of the effectiveness of cylindrical plume simulators for predicting jet-on boat-tail drag at Mach numbers up to 1.30. NASA TN D-7795.
Sjolander S. A. 1980 Eddy viscosity in two-dimensional and laterally strained boundary layers. Ph.D. Dissertation, University of Cambridge.
Spalding D. B. 1961 A single formula for the law of the wall. Trans. ASME E; J. Appl. Mech. 28, 455–458.Google Scholar
Thompson B. G. J. 1965 A new two-parameter family of mean velocity profiles for incompressible turbulent boundary layers on smooth walls. Aero Res. Counc. R & M 3463.Google Scholar
Wilmoth R. G. 1980 Viscous-inviscid calculations of jet entrainment effects on the subsonic flow over nozzle afterbodies. NASA-TP-1626.