ALGORITHM USING SPHERICAL COORDINATES TO CALCULATE DYNAMIC PRESSURE FROM 5-HOLE PRESSURE PROBE DATA

A 5-hole static pressure probe is currently being used to characterize the inflow of the Combined Experiment Rotor experiment. A new algorithm has been developed to calculate dynamic pressure (qx), angle-of-attack (a), and crossflow-angle (0) from the pressure probe data. The new algorithm uses a version of the dynamic pressure calibration surface that has been transformed into spherical coordinates. This simple transformation eliminates the need for an iterative solution process and is computationally stable. Improvements of four to five times in computational speed and the elimination of divergent solutions have been demonstrated.