Analysis of numerical simulation and test of the separated flow field in solid rocket motor nozzle

Numerical simulation and test of the separated flow field in a solid rocket motor nozzle with large expansion ratio were carried out. In order to guide the test, pressure distribution and the position of separation point of the flow field on nozzle wall were obtained by numerical simulation; by the test, the accuracy of the computation model was validated, then the different gas flow characteristics before and after the separation point were revealed. Results show that internal flow field in nozzle becomes more disorganized when the separation occurs and turbulent fluctuation phenomenon also exists in lower frequency band by spectrum analysis of the inspected points pressure before and after the separation point. This research could provide important reference for structure design, ground test and test analysis of nozzle with large expansion ratio.