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I updated gradU every time step as I have gradU in the data set for each time step. However, the there is no gradU stored in the lagrangian folder. As I have the position data and gradU field data, I want to use the particle position information to check the gradU stored in the lagrangain particle is correct. |
Hi Jie
I cannot quite following you. Do you want to store the gradU at particle centers into the Lagrangian folder or gradU has been stored but the data was not correct. If they was not stored, just add a new variable for your particle class and add this IO utility for it like other properties in particle class. The IO utility is implemented in the following function 1) constructor function like this Foam::solidparticle::solidparticle ( const Cloud<solidparticle>& cloud, Istream& is, bool readFields ) 2) readFields 3) writeFields 4) operator<< If gradU has been written into lagrangian folder but not correct. I think they are not updated. Note that the volTensorField gradU you declare in your createFields.H is not the field of gradU in particle center. The first is the gradU in the patchcenters and cellCenters, whereas the second is the gradu in several discrete points. regards, Junwei |
Hi JunWei
Sorry about the confusion. I tried to store the gradU at particle centers into the Lagrangian folder, but it only contains the fist particle. I added the following lines in the constructor: ###################################### Foam::solidParticle::solidParticle ( const Cloud<solidParticle>& cloud, Istream& is, bool readFields ) : Particle<solidParticle>(cloud, is, readFields) { if (readFields) { if (is.format() == IOstream::ASCII) { d_ = readScalar(is); is >> U_; //- ** velocity gradients is >> gradU_; } else { is.read ( reinterpret_cast<char*>(&d_), //sizeof(d_) + sizeof(U_) //- **velocity gradients sizeof(d_) + sizeof(U_) + sizeof(gradU_) ); } } // Check state of Istream is.check("solidParticle::solidParticle(Istream&)") ; } ##################################### and I asked it to write out the gradU #################################### void Foam::solidParticle::writeFields(const Cloud<solidParticle>& c) { Particle<solidParticle>::writeFields(c); label np = c.size(); IOField<scalar> d(c.fieldIOobject("d", IOobject::NO_READ), np); IOField<vector> U(c.fieldIOobject("U", IOobject::NO_READ), np); //- **velocity gradients IOField<tensor> gradU(c.fieldIOobject("gradU", IOobject::NO_READ), np); label i = 0; forAllConstIter(Cloud<solidParticle>, c, iter) { const solidParticle& p = iter(); d[i] = p.d_; U[i] = p.U_; //- **velocity gradients gradU[i] = p.gradU_; i++; } d.write(); U.write(); //- **velocity gradients gradU.write(); } #################################### in the lagrangain folder, gradU only contains: FoamFile { version 2.0; format ascii; class tensorField; location "101.3"; object gradU; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // 1301{(0 0 0 0 0 0 0 0 0)} // ************************************************** *********************** // Instead of having all zeros in 1301{(0 0 0 0 0 0 0 0 0 0)}, it should have the gradU for all 1301 particles. I have no problem with U. |
Hi JunWei
I have attached my solidparticleIO.C here. It looks like it counts the number of particles in the gradU in lagrangian folder, but all the gradU for each particle is not there. |
Hi Jie
1301{(0 0 0 0 0 0 0 0 0 0)} means there are 1301 particles with the same value. tensor::zero. The possible reason is that the gradU of the particle location was not updated. The attachment you provided is right I think. Regards, Junwei |
Hi JunWei
I am still looking at how to update the gradU for each of the particle and I came across couple question as follows: 1. if gradU has 1301{(0 0 0 0 0 0 0 0 0 0)} at each time step, it means all the gradU stored in the particles are zero? 2. In the particle.C: template<class ParticleType> 00411 void Foam::Particle<ParticleType>::transformPosition(const tensor& T) 00412 { 00413 position_ = transform(T, position_); 00414 } It says this transforms the physical properties of the particle. But in parcel.C void Foam:: parcel::transformProperties(const tensor& T) 00689 { 00690 U_ = transform(T, U_); 00691 } It says this transforms the position and physical properties of the particle. How come it uses the velocity U_ to transform the position of the particle and it use position_ to transform the position of the particle? Thank you very much. |
1) if gradU has 1301{(0 0 0 0 0 0 0 0 0 0)} at each time step, it means all the gradU stored in the particles are zero?
Yes 2) transform can be used in rotation. T is rotational tensor. Junwei |
figuring out how to update gradU.
Thanks for your time JunWei |
One quick question: if I need to do an inner product of a tensor "T" and a vector "a", should it be "T & a" instead of "a & T"?
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Dear Su Jun Wei,
I was trying to use your way to calculate the velocity gradient tensor. It works fine with one core. But error comes for parallel computing when try to access fvc::grad(). Do you have any idea? Best, ycui Quote:
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