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PHOENICS 软件培训. PHOENICS 软件的变量. 因变量( dependent variables ) 100 个 自变量( independent variables ) X Y Z t 辅助变量( auxiliary variables ) RHO1, ENUL. late time. early time. time. high. high. north. north. z. z. y. y. low. low. south. south. x. x. west. west. east. east.
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PHOENICS软件的变量 • 因变量(dependent variables) 100个 • 自变量(independent variables)X Y Z t • 辅助变量(auxiliary variables) RHO1, ENUL
late time early time time high high north north z z y y low low south south x x west west east east 离 散 示 意 图
PHOENICS软件求解的方程: 其离散式为: aPP=aNN + aSS + aEE + aWW + aHH + aLL + aTT + sources 其中: aP = aN + aS + aE + aW + aH + aL + aT(by continuity)
PHOENICS软件求解方法 1. Point by point: aPfPnew = aNfNold + aSfSold + aEfEold + aWfWold + aHfHold + aLfLold + aTfT + sources 收敛迟缓,适用于各变量强烈偶合
PHOENICS软件求解方法 2. Slabwise: aPfPnew - aNfNnew - aSfSnew - aEfEnew – aWfWnew = aHfHold + aLfLold + aTfT + sources Solve命令的默认解法,对抛物流有较大优越性
PHOENICS软件求解方法 3. Whole-field: aPfPnew - aNfNnew - aSfSnew - aEfEnew - aWfWnew - aHfHnew + aLfLnew = aTfT + sources 适合于弱非线性,如热传导; 压力修正方程通常用此方法
PHOENICS中的边界条件(源项) • PHOENICS默认(不设任何边界条件): 所有边界对流体不产生流入(出)、无摩擦、绝热,表现出对称面或轴的特征;phoenics设置边界条件以源项的形式加入。
PHOENICS中的边界条件(源项) • 传统源项,如压力梯度、粘性发热等已经在phoenics中内置,term命令控制; • 有限容积法离散方程,源项线性表达为:Sbc=TC(V-) ; T是几何因子,如面积或体积 对每个单元有:
PHOENICS中的边界条件(源项) • 每单元源项:
PHOENICS中的边界条件(源项) • PIL施加源项: • where and when? • T、C、V? Patch(name, type, ixf, ixl, iyf, iyl, izf, izl, itf, itl) Coval(name, variable, coefficient1, value1) Coval(name, variable, coefficient2, value2) variable是phoenics求解变量
PHOENICS中的边界条件(源项) • 固定值边界:C赋为大数(fixval),V取边界值
PHOENICS中的边界条件(源项) • 固定流率边界:C赋为小值,V取边界流率与C的商(C为fixflu,V取边界流率)
PHOENICS中的边界条件(源项) • 线性边界,如固定换热系数h(W/m2/K)与固定温度(K)的环境换热: Q = Sh(Tsur-Tp) 显然,T=S,h=C,V=Tsur Patch(heatloss, area, ixf, ixl, iyf, iyl, izf, izl, itf, itl) Coval(heatloss, tem1, h, Tsur)
PHOENICS中的边界条件(源项) • 层流wall边界:静止壁面对流体的层流剪应力 可以令 • 用wall型边界: 则只需:C=1.0
PHOENICS中的边界条件(源项) • 流入边界:所有质量流边界都是线性引入连续方程,压力为变量 • 流入边界如果与内部压力无关,则Cm取为fixflu,Vm取所加质量流 • 固定压力边界:压力固定,与质量流无关,Cm取大值,Vm取边界压力。由于数值计算需要,C并不取fixval,而取1000左右
EARTH的组织: • GROUND面向用户:
Q1文件24GROUP • TALK=T;RUN(1,1) • GROUP 1. Run title and other preliminaries • GROUP 2. Transience; time-step specification • GROUP 3. X-direction grid specification • GROUP 4. Y-direction grid specification • GROUP 5. Z-direction grid specification • GROUP 6. Body-fitted coordinates or grid distortion • GROUP 7. Variables stored, solved & named • GROUP 8. Terms (in differential equations) & devices • GROUP 9. Properties of the medium (or media) • GROUP 10. Inter-phase-transfer processes and properties • GROUP 11. Initialization of variable or porosity fields • GROUP 12. Convection and diffusion adjustments • GROUP 13. Boundary conditions and special sources • GROUP 14. Downstream pressure for PARAB=.TRUE. • GROUP 15. Termination of sweeps • GROUP 16. Termination of iterations • GROUP 17. Under-relaxation devices • GROUP 18. Limits on variables or increments to them • GROUP 19. Data communicated by satellite to GROUND • GROUP 20. Preliminary print-out • GROUP 21. Print-out of variables • GROUP 22. Spot-value print-out • GROUP 23. Field print-out and plot control • GROUP 24. Dumps for restarts • STOP
GROUND的应用 • Ground的24个group与q1相应group一一对应: • Q1-SET变量 • Logicals: CARTES, ONEPHS, PARAB, BFC,USEGRD, ... • Integers: NX, NY, NZ, LSWEEP, IZPRF, NXPRIN, ... • Reals: XULAST, RHO1, RHO2, RHO1A, ENUL, PRESSO, ... • Character: NAMGRD, NSAVE, ... • Real Arrays: PRNDTL, PRT, FIINIT, VARMIN, ...
数组名 类型 维数 参数 RG 实型 200 实数 IG 整形 200 整数 LG 逻辑型 100 逻辑值 CG 4位字符型 100 4位字符 Q1-GROUND交互数组:
GROUND的应用 • Q1-CONTROL变量: 时间步长:TLAST=GRND 物性参数:RHO1=GRND 边界条件:C=GRNDn,V=GRNDn … …
GROUND的应用 • FLOW VARIABLES: For Phase 1: P1, U1, V1, W1, R1, C1, C3, C5, .... C35 For phase 2: P2, U2, V2, W2, R2, C2, C4, C6, .... C34 Other: RS (shadow-phase volume-fraction), KE (kinetic energy) and EP (rate of dissipation of KE)
GROUND的应用 • F数组应用: • 变量在F数组中存储方式 • 变量在F数组中的位置: 每个变量片断在F数组中的起始位置; 每单元变量在该片断中的偏移量。
GROUND的应用 • 变量首地址及其偏移量: 首地址:L0VAR=L0F(VAR) 片断结构:
GROUND的应用 • 变量在片断中的偏移量: P单元:IY+NY*(IX-1) E单元:IY+NY*IX N单元:IY+1+NY*(IX-1) H单元:N*(IZ-1)*NX*NY+IY+NY*(IX-1) • 邻单元取值亦可用: EAST、NORTH、HIGH、OLD… …
GROUND的应用 • 在哪里添加自己的程序? • Ground的结构和每个group及section的功能 • GROUP 19:which section?
DO ISTEP=1, LSTEP ! Transience loop | Visit Sec 1: start of time-step | DO ISWEEP=1, LSWEEP ! Outer-iteration loop | | Visit Sec 2: start of sweep | | DO IZ=1, NZ ! Single-sweep loop | | | Visit Sec 3: start of IZ slab | | | DO ITHYD=1, LITHYD ! Hydrodynamic loop | | | | Visit Sec 4: start of iteration | | | | Solve equations | | | | Visit Sec 5: finish of iteration | | | END DO | | | Visit Sec 6: finish of IZ slab | | END DO | | Visit Sec 7: finish of sweep | END DO | Visit of Sec 8: finish of time step END DO
PLANT的应用 • 逐渐替代GROUND