Prediction methods for powered lift vehicle aerodynamics, phase 2

摘要

This report summarizes work done in the phase 2 project. A zonal method of iterative coupling between an inviscid code, VSAERO, and a viscous code, APPL, was employed. VSAERO, a low-order panel method, was modified to handle both an entire aircraft configuraton and a jet wake/surface. APPL uses an accurate second-order, iterative, alternating-direction-implicit (ADI) algorithm to integrate the parabolized Navier-Stokes equations in a single marching pass through the domain and solves the jet region with a three-dimensional pressure equation to recover the elliptic effects. The jet model in VSAERO is refined to improve the stability of boundary relaxation and also to maintain a boundary shape. A correlation study with the available experimental data has been carried out to establish the range of validity of the method using a jet on a plate, a no-jet model, a lift-jet-only model, and a vectored thrust model with lift jet. The results shown are in relative good agreement with the experimental data. However, it is indicated that a correct description of the geometry is a critical factor, and this study suggests further improvement in the coupling process is necessary to reflect strong entrainment modeling and to enhance usability.