SRF/MRF的使用问题？数值模拟中要定义旋转速度。

小龙

0_1492160946446_upload-f6cf43d7-b9a3-44a7-a5df-c48a08c052aa
如图所示的几何模型，入口为圆环的外侧，出口为圆环的内侧，有水流过，在圆环的上表面要有一个旋转速度，下表面是无滑移的，我应该怎么定义旋转速度，使用MRF可以实现吗？

CFD中文网

@小龙不，你只需要定义上表面的速度旋转就可以了，不需要别的参考系。

小龙

@cfd-china 那表面上的旋转速度怎么定义呢？可以给我详细的说一下吗？谢谢啦。

小龙

@cfd-china 您好，这个问题还在困扰着我，是用SRF定义上表面的旋转速度吗，还是其他的方法，您可以帮我解答一下吗？

李东岳

@小龙
你要做点数学运算，就是用网格点的位置表示出来速度的方向矢量，比如如果网格点在(1 1 1)，你的速度是(2 2 2)，那就就这样写：

    wallV
    {
        type            codedFixedValue;
	value 		uniform (0 0 0);
	redirectType	dummy; 
	code
	#{
	const fvPatch& boundaryPatch = this->patch(); 
        const vectorField& Cf = boundaryPatch.Cf(); 
        vectorField& U = *this;
	forAll(Cf,faceI)
	{
	    scalar x = Cf[faceI].x();
            scalar y = Cf[faceI].y();
            scalar z = Cf[faceI].z();
            v[faceI] = vector(2x, 2y, 2z);
	}
        #};
}

小龙

@李东岳速度是指线速度吗？OF有类似的自带算例吗？

CFD中文网

@小龙 OpenFOAM应该不存在相关现成的算例，你尝试过上面的代码了么？能否运行？:big_mouth:

小龙

@cfd-china 尝试过了，不能运行

小龙

@cfd-china 0_1485330951563_upload-2a6a3824-2ce9-4a18-9d5e-08a9ae5cfa12 麻烦您帮我看一下这样定义的旋转速度对吗，我对OpenFoam学习的还不够深入，感谢您对我的帮助。

赵一铭

你这个和壁面旋转速度还不一样，你的壁面旋转是那种平的旋转速度吧？像是顶盖驱动流那种平的速度？

小龙

@赵一铭嗯对，就是那种类似于顶盖驱动流的平的旋转速度，

赵一铭

岳哥那个代码提示什么错误？

小龙

@赵一铭提示了很多错误，我一会用电脑运行一下，截图您帮我看看，您先看看我在上面截图发的那个对吗，可以用吗？谢谢您了

赵一铭

@小龙
好的，最好贴文本上来，代码高亮一下。

小龙

@赵一铭嗯嗯，谢谢您了，我以前没发过，以后会注意的

小龙

@赵一铭我一会发个文本上来

小龙

@赵一铭

MOVINGWALL
{
    type            codedFixedValue;
    name    swirl;

    code
    #{
        const vector axis(0, 0, 1);

        vectorField v(2.0*this->patch().Cf() ^ axis);
        v.replace(vector::Z, 0);
        operator==(v);
    #};
    value           $internalField;
}

···

小龙

@赵一铭
这个是李东岳老师给的代码运行的错误

Create time

Create mesh for time = 0


SIMPLE: convergence criteria
    field p	 tolerance 0.01
    field U	 tolerance 0.001
    field "(k|epsilon)"	 tolerance 0.001

Reading field p

--> FOAM Warning : 
    From function Foam::Field<Type>::Field(const Foam::word&, const Foam::dictionary&, Foam::label) [with Type = double; Foam::label = int]
    in file /home/ubuntu/OpenFOAM/OpenFOAM-4.1/src/OpenFOAM/lnInclude/Field.C at line 317
    Reading "/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/p.boundaryField.INLET" from line 27 to line 28
    expected keyword 'uniform' or 'nonuniform', assuming deprecated Field format from Foam version 2.0.
--> FOAM Warning : 
    From function Foam::Field<Type>::Field(const Foam::word&, const Foam::dictionary&, Foam::label) [with Type = double; Foam::label = int]
    in file /home/ubuntu/OpenFOAM/OpenFOAM-4.1/src/OpenFOAM/lnInclude/Field.C at line 317
    Reading "/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/p.boundaryField.OUTLET" from line 32 to line 33
    expected keyword 'uniform' or 'nonuniform', assuming deprecated Field format from Foam version 2.0.
AMI: Creating addressing and weights between 1911 source faces and 1911 target faces
AMI: Patch source sum(weights) min/max/average = 0.999994, 1, 1
AMI: Patch target sum(weights) min/max/average = 0.924226, 1, 0.999254
Reading field U

Using dynamicCode for patch MOVINGWALL on field U at line 80 in "/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL"
Creating new library in "dynamicCode/dummy/platforms/linux64GccDPInt32Opt/lib/libdummy_998c505417ee368105406475ef07b1aa535fae1b.so"
Invoking "wmake -s libso /home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/dynamicCode/dummy"
wmakeLnInclude: linking include files to ./lnInclude
Making dependency list for source file fixedValueFvPatchFieldTemplate.C
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL: In member function ‘virtual void Foam::dummyFixedValueFvPatchVectorField::updateCoeffs()’:
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL:93:13: error: ‘v’ was not declared in this scope
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL:93:31: error: unable to find numeric literal operator ‘operator""x’
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL:93:31: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL:93:35: error: unable to find numeric literal operator ‘operator""y’
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL:93:35: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL:93:39: error: unable to find numeric literal operator ‘operator""z’
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL:93:39: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL:90:13: warning: unused variable ‘x’ [-Wunused-variable]
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL:91:20: warning: unused variable ‘y’ [-Wunused-variable]
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL:92:20: warning: unused variable ‘z’ [-Wunused-variable]
/home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL:87:22: warning: unused variable ‘U’ [-Wunused-variable]
/opt/openfoam4/wmake/rules/General/transform:8: recipe for target 'Make/linux64GccDPInt32Opt/fixedValueFvPatchFieldTemplate.o' failed
make: *** [Make/linux64GccDPInt32Opt/fixedValueFvPatchFieldTemplate.o] Error 1


--> FOAM FATAL IO ERROR: 
Failed wmake "dynamicCode/dummy/platforms/linux64GccDPInt32Opt/lib/libdummy_998c505417ee368105406475ef07b1aa535fae1b.so"


file: /home/xiaolong/OpenFOAM/xiaolong-4.1/run/xuanzhuan/0/U.boundaryField.MOVINGWALL from line 80 to line 84.

    From function void Foam::codedBase::createLibrary(Foam::dynamicCode&, const Foam::dynamicCodeContext&) const
    in file db/dynamicLibrary/codedBase/codedBase.C at line 206.

FOAM exiting

赵一铭

code
        #{
            // const vector axis(1, 0, 0);
            const fvPatch& boundaryPatch = this->patch();
            vectorField v = boundaryPatch.Cf();
            forAll(boundaryPatch, faceI)
            {
                v[faceI] = vector(boundaryPatch.Cf()[faceI].x(),0,0);//修改这个
            }

            //vectorField v(1, 1, 1);
            //v.replace(vector::X, 1.0);
            operator==(v);
        #};

试试这个，把速度初始化为网格边界面的x方向的值了即(value, 0, 0)，参考这个定义你自己的函数。

小龙

@赵一铭
感谢您，我还有两个问题：
这个是定义了绕x轴的旋转速度吗？
假如我的旋转速度是1500r/min，我该怎么换算呢，修改哪里呢？

李东岳

@小龙

你这个是需要做一些数学运算的，比如图上这些点的速度和坐标点的位置有关。知道方程之后就好办了。coding永远都不是问题，你试试先把方程写出来。

小龙

@李东岳好的，谢谢您的帮助