A flow state interpretation method for flight test measuring point positions
A technology of flight test and measuring point position, which is applied in the field of aerodynamics, can solve the problems of large amount of calculation, time-consuming, untimely interpretation, etc., and achieve the effect of improving accuracy and reducing the time of data processing
Active Publication Date: 2020-02-11
CHINA ACAD OF AEROSPACE AERODYNAMICS
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The main disadvantage of this flow state interpretation method is that it needs to supplement the full laminar flow and full turbulent flow calculation of a large number of ballistic points, which requires a large amount of calculation, takes a long time, and the interpretation is not timely
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[0022] For the flow state on the surface of the aircraft, it is usually interpreted based on the change of heat flow q, and the wall heat flow is the temperature normal gradient, and k is the thermal conductivity. For boundary layer flow, It is positively correlated with W(t), that is, the larger W(t), The larger; T'(t) is positively correlated with q, that is, the larger q, the larger T'(t); therefore, if W(t) decreases (ie Decrease), and T'(t) increases (q increases), indicating that it may only be caused by the increase of thermal conductivity k, which means that the flow state changes from laminar flow to turbulent flow, so this moment is the time when the measuring point is located from laminar flow to turbulent flow moment of transition.
[0023] Similarly, if W(t) increases and T'(t) starts to decrease, it means that the flow state changes from turbulent flow to laminar flow, and the corresponding moment is the transition moment from turbulent flow to laminar f...
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The invention relates to a method for interpreting flow states of locations of flight test measuring points. Design principles of the method are energy conservation and turbulence characteristics. Themethod includes acquiring temperature rise speeds T' (t) by means of computation according to temperature curves T (t) measured in flight tests; acquiring pu (t) curves according to flight test trajectories and pressure measured values; acquiring Reynolds Re curves according to the flight test trajectories; comparing the temperature rise speeds T' (t) and the pu (t) curves and indicating that themeasuring points turn into turbulence states when the temperature rise speeds T' (t) start to be increased and pu is diminished. The Re curves are used for assisting in interpreting the flow states.The method has the advantages that the method is based on heat-work conversion principles, measurement data of the flight tests and derivative data of the measurement data are utilized, and accordingly the flow states of the locations of the measuring points can be quickly interpreted without extra computation; the data processing time can be shortened to a great extent after the flight tests arecarried out, and the data can be basically processed in real time.
Description
technical field [0001] The invention belongs to the technical field of aerodynamics and is used for fluid state interpretation at the location of flight test measuring points. Background technique [0002] The boundary layer flow state includes laminar flow, turbulent flow, and transition from laminar flow to turbulent flow (transition refers to the transition stage from laminar flow to turbulent flow). Due to the different transport properties of mass, momentum, and energy between laminar flow and turbulent flow, the turbulent flow state The friction and heat flow under the air are 3-5 times that of the laminar flow. Therefore, the interpretation of the flow state is the basis for the prediction of the aerodynamic characteristics. [0003] At present, there are more and more flight tests on the boundary layer transition, so it involves the interpretation of the flow state at the position of the measuring point. The more commonly used method is to carry out full laminar flo...
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IPC IPC(8): G01M9/00
CPCG01M9/00
Inventor 杨武兵刘智勇沈清
Owner CHINA ACAD OF AEROSPACE AERODYNAMICS