Miniature Four Hole Probe for Three Dimensional Boundary Layer Measurements

The design, fabrication and calibration details of a miniature four hole probe for three-dimensional boundary layer measurements are presented in this paper. The probe has a nominal measuring area of 1 mm2 and has a nominal dimension of 0.4 mm in the boundary layer direction thus minimizing pressure and velocity gradient errors and wall vicinity errors. The probe is calibrated in an open jet calibration tunnel at a velocity of 50 m/s in the yaw and pitch angle range of + 40O at 5O interval. The calibration coefficients are defined, calculated and presented. The sensitivity of the calibration coefficients is also calculated and presented.