APPLICATION OF TRADITIONAL OIL-FLOW-VISUALIZATION TECHNIQUE IN DETERMINING SKIN-FRICTION FIELDS ON AXISYMMETRIC AFTERBODY MODEL

Abstract

This study evaluated the application of the traditional oil-flow-visualization technique in determining skin-friction fields for surface flow of an axisymmetric afterbody model at lowspeed conditions. Oil liquid, which was mixed of kerosene, titanium dioxide and oleic acid, was painted on the surface of model before experimental process. The movement of the oil was recorded by camera for data processing. The algorithm for extracting skin-friction fields was developed by the author and was validated. The method applied for boattail model. The results indicated that the traditional oil-flow-visualization technique provided sufficiently good outcomes for extracting skin-friction fields. Lagrange multiplier in range from 5 to 500 and number of selected pair images between 10 and 20 have a small effect on the skin-friction topology. The flow streamlines of the proposed method were also discussed detail in this study. Although the separation position was not captured well by the method, the reattachment position showed close results to previous observations. Consequently, the technique can be applied to analyze skin-friction fields of moving vehicles.