Flight and ground correlation method of natural transition test data of boundary layer

Abstract

The invention relates to a flight and ground correlation method of natural transition test data of a boundary layer. A test similarity criterion and a data fitting formula are adopted as design principles of the method. According to an implementation mode of the method, firstly, analysis of the differences between a flight and the ground is carried out, and main influence factors influencing transition are concluded; secondly, through fitting of existing ground tests and flight test data, modification formulas of the influence factors is constructed; finally, according to the modification formulas, extrapolation is conducted on ground test data to obtain a transition Reynolds number under a flight condition or correlation between the ground tests and the flight test data is achieved. The method has the advantages that since an emphasis is placed on the test similarity criterion, the influence quantities to be modified are reduced; through classification of the differences between the flight and the ground, the modification formula of each influence quantity in a decoupling form is constructed. Since the modification formula of each influence factor is obtained by fitting a great amount of test data, the reliability is high.

Description

technical field [0001] The invention belongs to the technical field of aerodynamics and is used for the study of the correlation between the sky and the earth of the natural transition data of the boundary layer. Background technique [0002] Boundary layer transition refers to the transition from laminar flow to turbulent flow. Due to the different transport properties of mass, momentum and energy between laminar flow and turbulent flow, the friction and heat flow in turbulent flow are 3-5 times that of laminar flow. The location of layer transitions has an important influence on the prediction of friction and heat flow. Friction and heat flow are important basis for aircraft design, therefore, transition position is the basic and important basis in aircraft design. [0003] Due to the complex shape of the aircraft, the transition phenomenon has also become very complicated. The ground wind tunnel test is currently the most objective technical means to reflect the transiti...

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Problems solved by technology

However, the wind tunnel test conditions cannot fully simulate the flight conditions. Since the transition is a strong nonlinear phenomenon, the difference between the heaven and the ground in these simulation conditions will bring about significant differences in the simulation results. That is to say, the wind tunnel test of the transition The results cannot be directly used for design under flight conditions, therefore, the development of a space-ground correlation method for transition test data becomes the key to transition application research

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