Method And Application Of Detection Of Flow Structures In Supersonic Flow With Multiple Wave Interaction

The flow structure around supersonic and notably hypersonic aircrafts is generally very complicated.Typical flow structures include shock waves,expansion waves and shear layers.The flow stuctures may interact themselves or with each other,leading to more complicated secondary flow structures,thus making the flowfield more complicated.These flow structures may be beneficial or harmful to the aircraft.In this thesis,we study detection methods of typical wave structures like shock waves,expansion waves and slip lines.Notably,a better shock detection method is provided.Based on these methods,an advanced post-processing platform capable of real application and incorporating detection methods of various structures is developed.The platform of detection of flow structures developed in this work can 1)read the data from various CFD software,2)display the conventional flow structures like contours,iso-surfaces,streamlines,velocity vector,etc;3)detect and pick up shock surfaces,expansion waves and slip lines;4)display graphically typical flow structures and pick up the flow parameters;and 5)display numerical schlieren picture.The method developed in this thesis reduces the difficulty of confusion of structures,loss of essential structures and display of false structures that exist in traditional methods.Automatic detection of flow structures given here is useful for analysis of flow structures in fundamental studies,for correctly identifying important flow structures,and for guiding grid refinement in CFD analysis.Two applications are considered in this thesis,one is the detection of wave structures in a scramjet inlet,the other is the flow structure of a new lift surface.Complex shock interactions in these applications are analyzed.The present method is developed for real complex geometry and flow and has the feature of easy operation and intuitive display,independent of the data,grid and geometry type.It greatly reduces the difficulty in flow structure analysis both for fundamental study and engineering application.