CAJ | 학술논문

为了提高涡粘性假设的湍流模型对于非稳态流动的求解精度，同时兼顾其对于稳态流动的求解性能，将雷诺应力项与连续变换方程（CSSE）结合而形成新的应力项，使其根据流场尺度、网格尺度及 Kolmogorov 尺度来自动调节当地的应力雷诺应力模化水平，避免网格因素在流场模拟中产生不利影响，改正了混合 RANS/LES 方法的速度型偏离对数率问题；同时，该方法并未引入显式亚格子模型（SGS），因此回避了亚格子系数确定对于流场模拟精度产生的影响，改善了湍流模型对于流动不稳定性的辨识精度。在湍流平板算例中，CSSE 方法计算的边界层速度型精度与雷诺平均方法（RANS）相当，而对于圆柱尾迹的模拟则证明了 CSSE 方法具有混合 RANS/LES 方法的优点，即能够准确模拟流动的不稳定性特征。
위료제고와점성가설적단류모형대우비은태류동적구해정도，동시겸고기대우은태류동적구해성능，장뢰낙응력항여련속변환방정（CSSE）결합이형성신적응력항，사기근거류장척도、망격척도급 Kolmogorov 척도래자동조절당지적응력뢰낙응력모화수평，피면망격인소재류장모의중산생불리영향，개정료혼합 RANS/LES 방법적속도형편리대수솔문제；동시，해방법병미인입현식아격자모형（SGS），인차회피료아격자계수학정대우류장모의정도산생적영향，개선료단류모형대우류동불은정성적변식정도。재단류평판산례중，CSSE 방법계산적변계층속도형정도여뢰낙평균방법（RANS）상당，이대우원주미적적모의칙증명료 CSSE 방법구유혼합 RANS/LES 방법적우점，즉능구준학모의류동적불은정성특정。
In order to get the higher precision of the unsteady flow predicted by using liner turbulence model as well as keep the capability of solving the steady flow,the Reynolds-stress term is combined with continuous scale switch equation(CSSE)to form one new stress term which can automatically adjust the local Reynolds-stress level according to the flow field scale,grid scale and Kolmogorov scale.The CSSE method eliminates the disadvantage of grid scale on the flow simulation,the problem of disagreement between the velocity profile obtained by the method of hybrid RANS/LES and the law of the wall is solved.Meanwhile, this method do not use the explicit sub-grid stress(SGS)model which can avoid the disadvantaged impact on the flow simulation caused by SGS coefficient,so the flow instability can be controlled more accurately .The simulations of the boundary flow of the plate and the flow over the cylinder both prove that CSSE method is robust.In the testcase of a turbulent flat-plate,the velocity profiles of flat-plate boundary layer solved by CSSE match with that solved by Reynolds averaged Navier-Stocks(RANS)method very closely,the simula-tion of cylinder wake proves that the CSSE method can precisely simulate the flow instability which is the ad-vantage of hybrid RANS/LES.