Computation of laminar flow over cavities
Abstract
A survey of the numerical simulation of cavity flows with aerodynamic applications is presented. Based on this information, a MacCormack TVD scheme was developed to solve the NavierStokes equations for laminar flow. The computations indicate that the oscillatory frequencies are essentially independent of wall temperature T(sub W), stagnation temperature T(sub 0), boundary layer thickness at separation delta(sub s) and unit Reynolds number. However, the magnitude of the pressure fluctuations depends strongly on T(sub w) and delta(sub s). High wall to edge temperature ratios produce a damping of the oscillations, with a corresponding decrease in drag. For supersonic flow below Mach 2, a fundamental frequency is produced which is consistent with the predictions of existing semiempirical methods, and which corresponds to a second mode of oscillation. Higher frequencies are found and these are harmonics of the fundamental frequency. For Mach numbers between 2 and 2.5, subharmonics are also present. At Mach 2.5, a first mode occurs which is also consistent with semiempirical methods. Higher frequencies also occur but they are not harmonics. The computations also indicate that thick boundary layers will damp the oscillations and reduce drag.
 Publication:

Ph.D. Thesis
 Pub Date:
 1990
 Bibcode:
 1990PhDT........11E
 Keywords:

 Cavitation Flow;
 Damping;
 Digital Simulation;
 Laminar Flow;
 Mathematical Models;
 NavierStokes Equation;
 Oscillations;
 Wall Pressure;
 Boundary Layers;
 Compressible Flow;
 Computational Fluid Dynamics;
 Drag;
 Stagnation Temperature;
 Supersonic Flow;
 Wall Temperature;
 Fluid Mechanics and Heat Transfer