Similarity Law Design Method for Aircraft Cargo Separation Wind Tunnel Free Flight Test

Abstract

The invention discloses a design method for the similarity law of the wind tunnel free flight test for the separation of aircraft mounted objects: (1), based on the fact that the separation of the wind tunnel test is equal to the angular displacement of the separation trajectory of the real aircraft, the time reduction ratio k is calculated t Scale with quality k m (2), according to the horizontal line displacement similar to the separation trajectory of the wind tunnel test and the separation movement trajectory of the real aircraft, the mass reduction ratio k is calculated m (3), according to the vertical displacement similarity between the separation trajectory of the wind tunnel test and the separation trajectory of the real aircraft, deduce the initial separation velocity v of the wind tunnel experiment model 0m Movement time t separated from the real aircraft s (4), when the real aircraft separation distance is the separation impact critical distance, the corresponding real aircraft separation movement time t s Substitute the initial separation speed of the model and the real aircraft separation movement time t s , so as to determine the final model initial separation velocity v 0m . The invention reduces the non-correspondence between model line displacement and angular displacement, and improves test reliability.

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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