Boundary layer on a static pressure probe

The paper compares the results of laminar boundary layer calculations for the incompressible flow past a static pressure probe in a uniform stream with experimental results. The probe is placed in the stream at zero incidence. Calculation methods were studied by which the laminar boundary layer was obtained by transforming by a change of variables the Prandtl equations so as to obtain a universal equation. The results of two one-parameter methods were compared: the classical Karman-Pohlhausen method, and the method of Saljnikov. Both methods indicate a separation point near the sphere-cylinder junction. The presence of a separation zone in the form of a long bulb was confirmed in visualization studies, and it was found not to disturb the establishment of a laminar boundary layer.