Spillage Drag Measurement with Aid of CFD for Small Supersonic Transport

Abstract

This paper describes a method of spillage drag measurement with aid of CFD at supersonic speeds. In a wind tunnel testing, the number of pressure data points is limited and is not enough to capture pressure distribution needed for an accurate calculation of spillage drag. In this method, a wind tunnel testing provides pressure data at twenty points, by which a CFD analysis is validated. Then, the pressure data obtained by the wind tunnel testing is corrected based on pressure distribution obtained by the CFD analysis. The spillage drag is calculated using corrected data. When the intake is at the supercritical condition, the spillage drag does not exist. The present method correctly shows the spillage drag of nearly zero at the supercritical condition, while the spillage drag calculated only by wind tunnel data is negative. In addition, the spillage drag obtained by the present method is increased as the intake mass flow ratio is decreased, which agrees with the general trend. These results support the effectiveness of the present method.