sixDoFRigidBodyMotion如何续算?
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大家好,请问大家在使用sixDoFRigidBodyMotion进行流固耦合的时候,在仿真完毕之后如果想要续算是怎么设置的?
我使用的是OpenFOAM V2306,使用的求解以下是我的dynamicMeshDict文件:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: v1912 | | \\ / A nd | Website: www.openfoam.com | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class dictionary; object dynamicMeshDict; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dynamicFvMesh dynamicOversetFvMesh; motionSolverLibs (sixDoFRigidBodyMotion); motionSolver sixDoFRigidBodyMotion; dynamicFvMesh dynamicOversetFvMesh; sixDoFRigidBodyMotionCoeffs { patches (cylinder); innerDistance 100; outerDistance 101; mass 10; centreOfMass (0.0 0.0 0.0); momentOfInertia (1 1 1.5625); g (0 0 0); rho rhoInf; rhoInf 1; report on; solver { type Newmark; } constraints { yLine { sixDoFRigidBodyMotionConstraint line; direction ( 0 1 0); } rotation { sixDoFRigidBodyMotionConstraint axis; axis (0 0 1); } } restraints { spring1 { sixDoFRigidBodyMotionRestraint linearSpring; anchor (0.0 0.0 0.0); refAttachmentPt (0.0 0.0 0.0); stiffness 10.96622711232151; damping 0.6283185307179585; restLength 0; } spring2 { sixDoFRigidBodyMotionRestraint linearAxialAngularSpring; axis (0 0 1); stiffness 1.7134729863002358; damping 0.09817477042468103; } } } // ************************************************************************* //
以下是正常仿真300s之后的log.overPimpleDyMFoam中最后一步和sixDoFRigidMotion和overset有关的输出:
Restraint spring1: attachmentPt - anchor (0 -0.367945 0) spring length 0.367945 force (-0 4.0584 -0) Restraint spring2: angle 0.516284 moment (0 0 -0.883591) 6-DoF rigid body motion Centre of rotation: (0 -0.368716 0) Centre of mass: (0 -0.368716 0) Orientation: (0.869769 -0.493459 0 0.493459 0.869769 0 0 0 1) Linear velocity: (0 -0.372264 0) Angular velocity: (0 0 -0.107739) inverseDistance : detected 2 mesh regions zone:0 nCells:50721 voxels:(40 40 1) bb:(16.9781 3.77358 -0.500006) (20.9906 8.00001 0.500006) zone:1 nCells:2280 voxels:(40 40 1) bb:(-72 -40 -2.50004) (-40 -24 -1.49996) Overset analysis : nCells : 53001 calculated : 52701 interpolated : 189 (from local:0 mixed local/remote:0 remote:189) hole : 111
如果我想续算,直接修改controlDict中的endTime显然是会出现问题的,它会使用原来的dynamicMeshDict中的数据作为300s的初值,导致计算无法正常进行。
而如果我参照最后一步的输出修改dynamicMeshDict文件:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: v1912 | | \\ / A nd | Website: www.openfoam.com | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class dictionary; object dynamicMeshDict; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dynamicFvMesh dynamicOversetFvMesh; motionSolverLibs (sixDoFRigidBodyMotion); motionSolver sixDoFRigidBodyMotion; sixDoFRigidBodyMotionCoeffs { patches (cylinder); innerDistance 100; outerDistance 101; mass 10; // centreOfMass (0.0 0.0 0.0); centreOfMass (0 -0.368716 0); momentOfInertia (1 1 1.5625); orientation (0.869769 -0.493459 0 0.493459 0.869769 0 0 0 1); velocity (0 -0.372264 0); angularMomentum (0 0 -0.1683421875); // angularVelocity (0 0 -0.107739); g (0 0 0); rho rhoInf; rhoInf 1; report on; solver { type Newmark; } constraints { yLine { sixDoFRigidBodyMotionConstraint line; direction ( 0 1 0); } rotation { sixDoFRigidBodyMotionConstraint axis; axis (0 0 1); } } restraints { spring1 { sixDoFRigidBodyMotionRestraint linearSpring; anchor (0.0 0.0 0.0); // anchor (0 -0.368716 0); // refAttachmentPt (0.0 0.0 0.0); refAttachmentPt (0 -0.368716 0); stiffness 10.96622711232151; damping 0.06283185307179585; restLength 0; } spring2 { sixDoFRigidBodyMotionRestraint linearAxialAngularSpring; axis (0 0 1); stiffness 1.7134729863002358; damping 0.009817477042468103; // referenceOrientation 0; } } } // ************************************************************************* //
首先根据最后一步的数据修改dynamicMeshDict文件我不知道会不会带来新的误差,然后这种方法也没有明显效果,以下是修改后续算的第一步输出:
Restraint spring1: attachmentPt - anchor (0 -0.368716 0) spring length 0.368716 force (-0 4.06681 -0) Restraint spring2: angle 0.516062 moment (0 0 -0.883201) 6-DoF rigid body motion Centre of rotation: (0 -0.369639 0) Centre of mass: (0 -0.369639 0) Orientation: (0.869901 -0.493226 0 0.493226 0.869901 0 0 0 1) Linear velocity: (0 -0.371839 0) Angular velocity: (0 0 -0.10837) inverseDistance : detected 2 mesh regions zone:0 nCells:50721 voxels:(230 230 1) bb:(-8.00004 -8.00004 -0.500036) (24 8.00004 0.500036) zone:1 nCells:2280 voxels:(230 230 1) bb:(-0.999904 -1.00093 -0.500003) (1.0001 0.99908 0.500003) Overset analysis : nCells : 53001 calculated : 52683 interpolated : 202 (from local:202 mixed local/remote:0 remote:0) hole : 109
6-DoF相关的输出,通过修改dynamicMeshDict已经和前面比较接近了,但是zone 0, zone 1相关的输出有些差异,同时力系数突然变得很大:
forceCoeffs forceCoeffs write: Coefficient Total Pressure Viscous Internal Cd: -734104 -733933 -171.164 0 Cd(f): -367052 -366966 -85.5821 0 Cd(r): -367052 -366966 -85.5821 0 Cl: -458471 -457934 -537.556 0 Cl(f): -295374 -294999 -375.408 0 Cl(r): -163097 -162935 -162.148 0 CmPitch: -66138.8 -66032.2 -106.63 0 CmRoll: -7.89329e-15 -7.89337e-15 7.8177e-20 0 CmYaw: 8.40485e-15 8.40299e-15 1.86337e-18 0 Cs: 2.00416e-14 2.00378e-14 3.83127e-18 0 Cs(f): 1.84257e-14 1.84219e-14 3.779e-18 0 Cs(r): 1.61596e-15 1.61591e-15 5.22695e-20 0 writing force and moment coefficient files.
导致后续计算无法正常进行(时间步长变得很短)。
所以我想请教一下大家在使用sixDoFRigidMotion进行流固耦合仿真的时候,如果想要续算有什么好方法吗?因为似乎openfoam没有保存sixDoFRigidMotion的相关参数(如质心位置、速度、加速度等)。
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老师您好,我想请问一下关于字典中关键词的含义
innerDistance 100;
outerDistance 101;再找到的一个介绍中这样解释:innerDistance 内的任何内容直接将网格节点作为刚体移动。在innerDistance 和outerDistance 之间,网格节点变形。在outerDistance 之外,不会发生变形。outerDisatance永远大于innerDistance。
想请问一下老师,这个数值单位是m(米)吗,如果是,这个距离远大于建立的模型的尺寸,我在很多算例都看见是这么设置的,那么这两个关键词的意义是什么。