Accession Number:

ADA125392

Title:

Calculation and Measurement of Separated Turbulent Boundary Layers.

Descriptive Note:

Technical memo.,

Corporate Author:

ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (ENGLAND)

Report Date:

1982-10-01

Pagination or Media Count:

39.0

Abstract:

An inverse integral prediction method for the development of separated turbulent boundary layers developed from the lag-entrainment method is described. The inverse method uses the concept of equilibrium separated boundary layer flows and the predicted characteristics of such flows will be compared with measurements which represent the first known demonstration that equilibrium separated boundary layers can be realised experimentally. In these experiments the data were obtained with a single-component laser Doppler anemometer usually set up to measure streamwise components of mean velocity and turbulence intensity in addition, however, one pair of profiles of the mean velocity and turbulence intensity normal to the wall was obtained. The separated flow on a NACA 4412 aerofoil has been measured by Wadcock using the flying hot-wire technique. It is shown that predicted values of momentum thickness agree with the measured values but that the calculation predicts a pressure rise in the separated region whereas the pressure is almost constant in the experiment. The result of introducing second order effects into the calculation is shown. The equivalent inviscid flow is constructed and the matching of the equivalent and real flows is considered.

Subject Categories:

  • Numerical Mathematics
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE