400w 网格计算 水翼空化问题
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大家好！
最近再尝试用LES模拟水翼空化流动，用了400W的网格和interPhaseChangeFoam求解器，前期计算发现比较稳定，到0.3s之后就突然不正常了，有没有人用比较密的网格计算过水翼空化？
我原始设置的是固定时间步2.5*e-06,我感觉可能是时间步有点大了，但更改之后效果也不是很明显
ps:我之前用200w网格计算，效果很好，并没有出现类似的问题
下图是监控的 云空化空穴体积随时间变化图，前面好好地，后面就有问题了。。。
controlDict文件代码
// Foam Application Class application interPhaseChangeFoam; // Start point of run //startFrom latestTime; startFrom latestTime; // Calculation start time startTime 0;//0.399;//0; // End point of run stopAt endTime; // Calculation end time endTime 0.5;//0.9;//5.0e-2; // Calculation time step deltaT 2.5e-06;//2.0e-5;// // Type of write output control writeControl adjustableRunTime; // Interval with which the results are output writeInterval 1.0e-3; // Limits number of time directories before overwriting cycleWrite 0; // Write Format writeFormat ascii; // Significant figures of written ASCII data writePrecision 6; // Write Compression writeCompression uncompressed; // Time directories name format timeFormat general; // Decimal precision of time directory names timePrecision 6; // Can parameters be modified during run time? runTimeModifiable yes; // Automatic adjustment of time step? adjustTimeStep off; // maxCo maxAlphaCo 0.99; // 0.2; Victor Changes to remain with courant number < 1 // maxDeltaT maxDeltaT 1e-2; // 1; Control the changes of delta calculation for a courant number < 1fvSchemes文件
ddtSchemes { default Euler; } gradSchemes { default Gauss linear; } divSchemes { default none; div(phi,alpha) Gauss upwind; div(phirb,alpha) Gauss linear; div(phi,rho) Gauss limitedLinear 1; div(rhoPhi,U) Gauss upwind; div(phi,thermo:rho.water) Gauss upwind; div(phi,thermo:rho.air) Gauss upwind; div(rhoPhi,T) Gauss upwind; div(rhoPhi,K) Gauss upwind; div(phi,p) Gauss upwind; div(phi,k) Gauss upwind; div(rhoPhi,omega) Gauss limitedLinear 1; div(phi,omega) Gauss upwind; div(rhoPhi,k) Gauss upwind; div(((rho*nuEff)*dev2(T(grad(U))))) Gauss linear; } laplacianSchemes { default Gauss linear uncorrected; } interpolationSchemes { default linear; } snGradSchemes { default uncorrected; } wallDist { method meshWave; }一般这样 网格量很大的情况，用LES计算非定常问题，需要注意什么呢？
求各位指点！
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把你log文件信息贴一下，
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.log文件最前面的参数
Create time Create mesh for time = 0.195 PIMPLE: No convergence criteria found PIMPLE: Operating solver in PISO mode Reading field p_rgh Reading field U Reading/calculating face flux field phi AMI: Creating addressing and weights between 43430 source faces and 43430 target faces AMI: Patch source sum(weights) min/max/average = 0.999998, 1, 1 AMI: Patch target sum(weights) min/max/average = 0.999994, 1, 1 Creating phaseChangeTwoPhaseMixture Selecting phaseChange model SchnerrSauer Selecting incompressible transport model Newtonian Selecting incompressible transport model Newtonian Selecting turbulence model type LES Selecting LES turbulence model WALE Selecting LES delta type cubeRootVol LES { LESModel WALE; turbulence on; printCoeffs on; delta cubeRootVol; cubeRootVolCoeffs { deltaCoeff 1; } PrandtlCoeffs { delta cubeRootVol; cubeRootVolCoeffs { deltaCoeff 1; } smoothCoeffs { delta cubeRootVol; cubeRootVolCoeffs { deltaCoeff 1; } maxDeltaRatio 1.1; } Cdelta 0.158; } vanDriestCoeffs { delta cubeRootVol; cubeRootVolCoeffs { deltaCoeff 1; } smoothCoeffs { delta cubeRootVol; cubeRootVolCoeffs { deltaCoeff 1; } maxDeltaRatio 1.1; } Aplus 26; Cdelta 0.158; } smoothCoeffs { delta cubeRootVol; cubeRootVolCoeffs { deltaCoeff 1; } maxDeltaRatio 1.1; } Ce 1.048; Ck 0.094; Cw 0.325; } Reading g Reading hRef Calculating field g.h No finite volume options present Courant Number mean: 0.00975387 max: 1.87647 Starting time loop forces forceCoeffs1: Not including porosity effects forceCoeffs forceCoeffs1: Not including porosity effects fieldAverage fieldAverage1: Restarting averaging for fields: U iters = 78001 time = 0.195002 alpha.water iters = 78001 time = 0.195002 p iters = 78001 time = 0.195002 surfaceFieldValue patchAverage: total faces = 9879 total area = 0.003969发散之后输出的内容
Courant Number mean: 0.00975777 max: 2.3062 Time = 0.34437 smoothSolver: Solving for alpha.water, Initial residual = 2.45197e-06, Final residual = 4.99732e-09, No Iterations 1 Phase-1 volume fraction = 0.997016 Min(alpha.water) = 8.9353e-06 Max(alpha.water) = 1 MULES: Correcting alpha.water Liquid phase volume fraction = 0.997016 Min(alpha.water) = 8.9353e-06 Max(alpha.water) = 1 GAMG: Solving for p_rgh, Initial residual = 1.23064e-05, Final residual = 6.14351e-08, No Iterations 1 GAMGPCG: Solving for p_rgh, Initial residual = 1.53786e-06, Final residual = 9.23801e-09, No Iterations 1 ExecutionTime = 184925 s ClockTime = 186563 s fieldAverage fieldAverage1 write: Calculating averages Courant Number mean: 0.00975777 max: 2.30292 Time = 0.344373 smoothSolver: Solving for alpha.water, Initial residual = 2.45241e-06, Final residual = 5.00226e-09, No Iterations 1 Phase-1 volume fraction = 0.997016 Min(alpha.water) = 8.93479e-06 Max(alpha.water) = 1 MULES: Correcting alpha.water Liquid phase volume fraction = 0.997016 Min(alpha.water) = 8.93479e-06 Max(alpha.water) = 1 GAMG: Solving for p_rgh, Initial residual = 1.21562e-05, Final residual = 6.58046e-08, No Iterations 1 GAMGPCG: Solving for p_rgh, Initial residual = 1.52149e-06, Final residual = 1.02397e-08, No Iterations 1 ExecutionTime = 184928 s ClockTime = 186566 s fieldAverage fieldAverage1 write: Calculating averages刚才和别人交流，感觉自己的离散格式都是一阶的，可能耗散有点大，感觉自己还要去试一试。。
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一阶格式更加稳定，在发散的情况下追求高阶格式会更加发散，为何不把可调节时间不长开启？
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