Development of a New Wall Shear Stress Gauge for Fluid Flows
Abstract
A new technique has been developed to measure the wall shear stress and its direction in the turbulent boundary layer. This technique involves the measurement of torque upon a very small cylindrical body placed above the wall deep in the viscous sublayer, so that the device is operating in the creeping flow regime. The method of approach has involved calibration tests on a gauge 8 mm. long by 0.8 mm. in diameter, located in uniform shearing flow of glycerol created in a cone and plate apparatus. Our theoretical, computational and experimental results show that the torque has a linear relation with the wall shear stress. The gauge response is reversed for reversing the flow. By directivity measurements using this gauge, maximum wall shear stress direction and its magnitude are obtained. Linear response is obtained up to Reynolds number 3.2 which was the highest we could get in our apparatus. A spectral element code, Nekton, is used for determining the creeping flow about the gauge. There is a very good agreement between the experimental and computational results. Keywords: Shear stress gauge; Stokes flow.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1988
- Accession Number
- ADA199745
Entities
People
- Patrick Leehey
- Yuksel Gur
Organizations
- Massachusetts Institute of Technology