Similarity law design method for free flight test of aircraft mounted separation wind tunnel

Abstract

The present invention discloses a similarity law design method for a free flight test of an aircraft mounted separation wind tunnel. The method comprises: based on that angular displacements of the wind tunnel test separation trajectory and the real aircraft separation motion trajectory are equal, deriving a relation between the time reduction ratio kt and the mass reduction ratio km; (2) according to the similarity between horizontal line displacements of the wind tunnel test separation trajectory and the real aircraft separation motion trajectory, calculating the mass reduction ratio km; (3)according to the similarity between vertical displacements of the wind tunnel test separation trajectory and the real aircraft separation motion trajectory, deriving the relation between the wind tunnel test model initial separation velocity v0m and the real aircraft separation motion time ts; and (4) when the real aircraft separation distance is the separation influence critical distance, substituting the corresponding real aircraft separation motion time ts into the relation between the model initial separation velocity v0m and the real aircraft separation motion time ts so as to determinethe final model initial separation velocity v0m. According to the method provided by the present invention, the non-correspondence between the model line displacement and the angular displacement is reduced, and the reliability of the test is improved.

Description

technical field [0001] The invention relates to free flight test parameters, in particular to a similarity law design method for a free flight test in a wind tunnel for aircraft load separation, and belongs to the field of aerospace engineering. [0002] technical background [0003] The aircraft model wind tunnel test plays an important role in the initial stage of aircraft development. A major feature of the wind tunnel test is that various parameters of the real aircraft are similarly scaled, and the test is carried out on the scaled model. The data obtained from the test are reversed by the similar scale formula. All kinds of aerodynamic parameters of the real aircraft can be obtained through directional calculation. The wind tunnel free flight separation test is an unsteady test method. Since the test model has no support interference, it can more realistically simulate the actual separation characteristics. Ejection of buried weapons, separation between stages, throwin...

AI Technical Summary

Problems solved by technology

Therefore, the previous tests could not fully meet the requirements of the law of similarity, and the test errors were relatively large. The accuracy and accuracy of the test results have been questioned by the outside world.

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