CAJ | 학술논문

为了解风洞阻塞效应对起落架气动噪声测量的影响，用基于 S—A 湍流模式的延迟分离涡模拟（DDES）对四轮基本起落架模型进行了数值模拟。通过不同截面积的滑移壁面计算域模拟模型安装在不同截面积风洞中的效应，并通过将底面和侧面设为远场边界条件模拟了无风洞起落架的流动条件。阻塞度从0变化到8．8％，根据所得到的非定常流场计算了时均表面压力分布和表面声压级分布。计算显示表面声压级总体上随阻塞度增大而减小；存在一个4％～5％的阻塞度阈值范围，在此范围内表面声压级发生突然变化，大于或小于该阈值范围时表面声压级受阻塞度的影响不大；对阻塞度变化最敏感的部件为前轮，而后轮最不敏感。这说明不同阻塞度下模型的气动噪声特性与平均流动特性密切相关。
위료해풍동조새효응대기락가기동조성측량적영향，용기우 S—A 단류모식적연지분리와모의（DDES）대사륜기본기락가모형진행료수치모의。통과불동절면적적활이벽면계산역모의모형안장재불동절면적풍동중적효응，병통과장저면화측면설위원장변계조건모의료무풍동기락가적류동조건。조새도종0변화도8．8％，근거소득도적비정상류장계산료시균표면압력분포화표면성압급분포。계산현시표면성압급총체상수조새도증대이감소；존재일개4％～5％적조새도역치범위，재차범위내표면성압급발생돌연변화，대우혹소우해역치범위시표면성압급수조새도적영향불대；대조새도변화최민감적부건위전륜，이후륜최불민감。저설명불동조새도하모형적기동조성특성여평균류동특성밀절상관。
In order to provide a basis and some references for experimental study on aerody—namic noise of landing gears,a numerical simulation is carried out for a four—wheel rudimentary landing gear (RLG)model using the delayed detached eddy simulation (DDES)based on the S—A turbulent model.Slip wall boundary condition with different section areas are used to mimic wind tunnels with different sizes,and the non—wind—tunnel case is simulated with far field boundary conditions for the side walls and the floor.The blockage ratioβis varied from 0 to 8.8%.Time—averaged surface pressure coefficient and surface sound pressure level (SPL)are calculated from the simulated unsteady flow field.The results show that the mean surface SPL decreases with in—creasingβin general.There is a thresholdβranged of roughly 4% ~ 5%.The mean surface SPL varies sharply whenβis within this range,and is insensitive withβwhen it is out of this range. The mostβ—sensitive part is the front wheel,while the most insensitive is the back wheel.This demonstrates a close relation between the aeroacoustic properties and mean flow properties at dif—ferent blockage ratios.