Method of measuring friction stress on interference surface of oil film

Abstract

The invention discloses a method of measuring friction stress on an interference surface of an oil film. The method comprises the following specific steps: step 1, obtaining a variable relationship of a viscosity coefficient [mu] of the oil film when time changes between a time t1 and a time t2, and measuring the thicknesses of the oil film at the time t1 and the time t2; step 2, setting an initial friction stress t0, calculating a thin oil film equation according to the variable relationship of the viscosity coefficient [mu] of the oil film when time changes, the thickness of the oil film at the time t1 and a numerical value, and adopting explicit time-marching to arrive at the time t2, so as to calculate the thickness of the oil film at the time t2; step 3, comparing the thickness of the oil film calculated at the time t2 with the thickness of the oil film measured at the time t2, correcting the friction stress t0 according to a comparison result, and carrying out explicit time-marching to the time t2 from the beginning of the time t1 again, wherein the t0 is the solved friction stress t after the circulation when the thickness of the oil film calculated is consistent to the thickness of the oil film measured. According to the method provided by the invention, the friction stress on the interference surface of the oil film can be obtained.

Description

technical field [0001] The invention relates to the technical field of test fluid mechanics, and discloses a method for measuring friction stress on an oil film interference surface. Background technique [0002] Frictional resistance plays a very important role in the design of aircraft. For commercial aircraft, the frictional resistance accounts for almost 40% to 50% of the total resistance in the cruising state. It is estimated that reducing the resistance by 1% can increase about 10 passengers [1], both in terms of economic benefits and energy conservation and environmental protection. In terms of aspects, drag reduction is very important; for hypersonic powered aircraft, frictional resistance accounts for 30% of the total resistance, which is directly related to whether the aircraft can obtain positive thrust and whether the design scheme is successful; For re-entry gliding weapons, the size of frictional resistance directly affects its range, which is related to the s...

AI Technical Summary

Problems solved by technology

[0021] Aiming at the technical problem that the above-mentioned friction stress measurement method does not consider the change of the viscosity coefficient or adopts a simple average method for the change of the viscosity coefficient, resulting in a large error in the measurement result, the present invention proposes a new oil film interference surface friction stress measurement method

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