Embedded cavity drag in steady and unsteady flows
Abstract
The numerical solution of the laminar boundarylayer flow over an embedded cavity is studied. The purpose is to examine the relevant drag characteristics of laminar cavity flow. The solution field is obtained in terms of velocity and vorticity variables, with the stream function and pressure derivable from the directly computed variables. An analysis and comparison is made among four square cavities, ranging in size from 0.25 to 1.00 boundarylayer thicknesses deep. The dominant flow features are examined in the vicinity of the cavity by means of the stream function and isovorticity contours. The dominant physics in the overall drag characteristics of the flow is examined by an analysis of the pressure and wall shear stress distributions in the cavity, and upstream and downstream of the cavity. Pressure forces and frictional forces in, and in the vicinity of, the cavity are determined. Stress relaxation distances, both upstream and downstream of the cavity, are calculated and analyzed. The flow dynamics of the boundarylayer flow over an embedded cavity is summarized. Finally, the relevance of the results to the control of flow separation in such flows is discussed.
 Publication:

National Aeronautics and Space Administration Report
 Pub Date:
 December 1983
 Bibcode:
 1983nasa.reptT....G
 Keywords:

 Aerodynamic Drag;
 Boundary Layer Flow;
 Cavities;
 Laminar Boundary Layer;
 Pressure Drag;
 Unsteady Flow;
 Boundary Layer Control;
 Boundary Layer Separation;
 Cavity Flow;
 Flow Characteristics;
 Flow Equations;
 Flow Velocity;
 Problem Solving;
 Shear Stress;
 Stress Distribution;
 Time Dependence;
 Vorticity;
 Fluid Mechanics and Heat Transfer