An investigation of secondary flow control in a diffusing S-duct inlet

The objective of this research is to study ways how to reduce distortion at exit of a diffusing S-duct inlet. For this purpose, vortex generators (VGs) were used. Prediction for bare S-duct was compared with flight test to validate the credibility of the numerical method. Reported herein are results for the duct with vortex generators at three different locations. Secondary flow in the three ducts was compared to each other at six cross section, distortion and pressure recovery were also compared. The results show that distortion was improved effectively but pressure recovery was not.