The method of experimental determination of tangential stresses on the surface of flow around with a gaseous medium

Abstract

Experimental research of the force load on the flow around surface is important for the design of aircraft and gas transport systems. The main parameter is the tangential stress, which is maximum in the boundary layer on the flow around surface. The velocity in the boundary layer and its thickness affect the tangential stresses that arise during the flow of the medium. They also have an influence on the friction coefficient, which characterizes the pressure losses. In the work, the method of experimental measurement of velocity on the flow around surface is considered, and an information and measurement system is proposed for determining the tangential stresses on the flow around surface based on the flow velocity measurement in the boundary layer. The algorithm of the measurement technique is presented in the form of a functional structural scheme of the laminar boundary layer on the surface of the flow around. The sensor for measuring the velocity in the boundary layer is installed at characteristic points namely at x distance from the front border of the flow around surface, and also at y height from the surface of the boundary layer. The results of the planned factorial experiment of air flow around the surface are given. The factors were the v 0 velocity of the air flow entering the flow around surface, the x distance from the edge of the surface, the y distance from the surface along the thickness of the layer. The response criterion was the calculated value of the tangential stress based on the vx measured flow velocity at a given point of the boundary layer. The developed method of studying the velocity distribution and determining the tangential stresses on the surface of the flow around under a dynamic boundary layer makes it possible to determine with high discreteness the parameters of the process of the surface around flow of a Newtonian gaseous medium.