Abstract:

An experimental investigation of aerodynamic characteristics of porous plates is performed in order to develop a reliable boundary layer condition for the numerical simulation of the flow with boundary layer suction. In the experiments, the ratio t/d of the plate thickness to the hole diameter ranges from 0.1 to 2.67 and the porosity ε of the plate from 6.3% to 23%. The experimental results show that the average Mach number in the hole relates with pressure drop over the porous plate, the ratio of the plate thickness to the hole diameter and the porosity of the plate. The Mach number in the hole will increase with the increase of pressure drop over the porous plate for a given plate. When the pressure drop reaches a certain value, the average Mach number in the hole will remain a constant value and the flow in the hole reaches the critical state. An empirical relation about the Mach number in the hole, pressure drop over the porous plate, the ratio of the plate thickness to the hole diameter and the porosity of the plate is established in this paper. In order to validate the empirical formula for boundary layer suction, numerical simulation of flow over a flat plate with boundary layer suction at free Mach number of 1.98, 1.58 and 0.8 is fulfilled by use of the empirical formula for boundary layer suction. The characteristics of flow over the porous plate are reasonably simulated and the flow rate of suction is in fairly good agreement with experimental data reported by B.P.Willis and J.Syberg. Therefore, the empirical formula described in this paper can be used in the numerical simulation of intake flow field with boundary layer suction.

Key words: boundary layer suction, numerical simulation, boundary layer condition, inlet, porous plate