| The rocker-type windshield wiper has a few times improvement on the driving, shape and control, but its working principle is always the same. Now the wiper can satisfy the basic work, but there are still many problems such as moving over the extreme position, too much noise, high resistance, and high lift, so it's still necessary to improve the performance of wiper.The most noteworthy problem is floating upward. When the car driving in the rain, the wiper is influenced by air flow and generated the aerodynamic lift, the lift makes the wiper's under pressure reducing, and then affects the driver's vision, thus easy to cause traffic accidents. However, now a lot of research work focused on friction characteristics, the study of the aerodynamic lift characteristics is still in its infancy. Some scholars have done a few preliminary resea rches, but all of them are confined to the steady-state numerical calculation. What's more the calculation results of different scholars vary widely and currently there exists no relevant verification testing to support numerical methods. T herefore, a more accurate and universally applicable method which combines test and numerical calculation is needed. In view of this situation, the followed research has been completed in this paper.1.This paper designed a test method and test equipment to test the aerod ynamic lift of wiper. By means of multi-point test method this paper completed the first wind tunnel of the aerodynamic lift of wiper. The test results showed that the aerodynamic lift force has influenced the wiper stability, and the aerodynamic lift forc e is determined by the blade structure.2.Based on the test results, this paper compared the adaptability of LES and turbulence model, and chose RNG k-? model to calculate the lift of wiper at last. T hen this paper made use of steady-state numerical methods to explore the mechanism of occurrence and its change rule.3.In order to study transient aerodynamic lift of the dynamic wiper, this paper made B-type three sections wiper as the research object, based on the dynamic mesh technology put forward a new strategy which is suitable for the simulation of complicated boundary and gross movement--Dynamic grid domain box, then combined the Dynamic grid domain box and User-Defined Functions to simulate the working state of the wiper and explore the transient aero dynamic lift.4.The wiper's working environment will be changed because of various factors affecting, in order to explore the working environment's influence on the aerodynamic lift, this paper made B-type three sections wiper as the research object, comb ined steady calculation and transient calculation to analyze the four main influence factors of wiper's aerodynamic lift, namely the windscreen angle, wiper angle of attack, crosswind and wiper speed of brush.5.This paper proposed a new kind of wiper wit h low aerodynamic lift--Wave type wiper, and optimized the location parameter of the "wave", then compared the new wiper with the original one, and illustrated the excellent aerodynamic lift performance of the new wiper. |
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