سال انتشار: ۱۳۸۶
محل انتشار: هفتمین همایش انجمن هوافضای ایران
تعداد صفحات: ۸
Nouroz Mohammad Nouri – Assistant professor, Hydrodynamics Laboratory, Iran University of Science and Technology
Mohammad Amin Sarshar – Graduate student, Hydrodynamics Laboratory, Iran University of Science and Technology, Member of Young Research Club of Iran
Ali Sarreshtedari – PhD. Student, Hydrodynamics Laboratory, Iran University of Science and Technology
The goal of this study was to develop an understanding of the effects that the geometric design and installation parameters of a direct skin friction gage have on the surrounding flow. This type of sensor uses a small movable head mounted flush to a wall such that the head is assumed to be exposed to the same shear stress from the flow as the surrounding wall. Reported results include effect analysis for various sensor design and installation cases in both laminar and turbulent flow. From the cases studied, laminar channel flow cases showed the importance of proper alignment of the sensor. Protrusion or recession of the sensing head concluded to be the dominant effect on resulting forces seen by the gage, changing the output by the value a bit more than the recession case for misalignments in ordinary sizes of headiameter. In the cases of strong pressure gradient, the thickness of the lip on the edge of the head also proved to have significant effect on the output, with a smaller lip thickness generally showing better performance than a large one. Zero lip thickness indicated the best accuracy ofesired wall shear result, since the pressure differences had little influence on the sensing head. For the turbulent flat plate case, misalignment remained the dominant effect on the sensor response. The gap size played an increased role in the high Reynolds number boundary layer cases. The lip was concluded to have no significant effect for a flow without a pressure gradient.