壁面温度分布的高超声速平板边界层稳定性分析及转捩预测

Stability and transition prediction of the hypersonic plate boundary layers for wall temperature distribution

针对来流马赫数为4.5、6.0和7.0的高超声速平板边界层,取30km高空处的气体参数,壁面为等温、绝热和温度分布等3种不同条件,采用eN方法进行转捩预测。其中,壁面温度分布条件下,在等温壁(冷壁)和绝热壁之间,给出4种流向分布进行分析。取扰动的初始幅值为0.3‰,以幅值达到1.5%作为转捩判断依据。结果表明:当温度为来流温度时,等温壁面条件的转捩位置最靠前,并随马赫数增大更加靠前;绝热壁面条件的转捩位置随马赫数增大而推后;壁面温度分布条件下,在相同时刻,马赫数越大,转捩位置越靠前。相同马赫数下,壁面温度较高者转捩位置较靠后(马赫数为7.0时,不完全满足此规律)。在马赫数为4.5和6.0时,绝热壁面条件转捩由第一模态主导,其余情况主导转捩的都是第二模态。

The transition prediction of the hypersonic boundary layer on a flat plate is investigated by using the e^N method under three different wall conditions including the isothermal,adiabatic and wall temperature distribution conditions.The gas parameters are taken as the corresponding air parameters at the height of 30km with the incoming flow Mach numbers 4.5,6.0 and 7.0.The calculation results are given and analyzed for four different cases of the wall temperature distribution.The initial disturbance amplitude is estimated to be 0.3‰.The transition is assumed to begin when the disturbance amplitude grows up to 1.5%.It can be seen that the transition location is most close to the leading edge in the case of the isothermal wall condition,and the transition location would move forward as the incoming flow Mach number increases.However,it would move backward as the incoming flow Mach number increases under the adiabatic wall condition.In the case of the wall temperature distribution condition,the transition location moves forward as the incoming flow Mach number increases.It is also found that the higher the wall temperature is,the further backward the transition location is(whereas,at Mach number 7.0,the result is different).In the adiabatic wall cases at the incoming flow Mach numbers 4.5 and 6.0,the transition locations are determined by the first mode waves,whereas the transition locations for the other cases are determined by the second mode waves.