Inviscid, Axisymmetric, Annular Wall Jet Impingement As an Idealization of Cascade Thrust Reversers

Abstract

An analytical solution to inviscid, axisymmetric, impinging wall jet flow is proposed as a limited idealization of internal flow within a cascade thrust reverser of an aircraft engine. Behavior of prior Bessel Series solution for round jets is critically examined, before extending the formulation to an annular jet with non-zero inner wall radius. Behavior and accuracy of prior spectral and finite difference algorithms are examined, leading to an efficient hybrid computational scheme. Jet inflow velocity profile has a deficit as well as non-zero vorticity-function at the inner radial boundary, as is typical in engine fan ducts. Inviscid recirculation appears at the impingement corner, the strength of which is made determinate by assuming locally constant vorticity-function. Results indicate that fan duct velocity profile deficit is a significant contributor to occurrence of a large recirculation zone that is experimentally observed within a fully deployed thrust reverser.