FAQs

QuickerSim CFD Toolbox has been tested on MATLAB versions from 2016b onwards.

 

The installation file (.mlapinstall format) can be downloaded after filling out a short questionnaire under the following link: DOWNLOAD

 

The licensing process complies with MATLAB's licensing policy – the license file is valid only on the operating system's user account on which the file was generated. For that reason, one license file cannot be used on 2 or more computers. Furthermore, the activation file must be generated with a .mat extension. Some older versions of MATLAB generate activation files with extensions such as .rpt or .mldatx which are not supported.

Since activation files are not processed automatically, license request are answered during the working hours of the company – 9am to 5pm UTC.

QuickerSim CFD Toolbox for Matlab is not compatible with Simulink at this stage of development.

Import of invalid GMSH meshes can result in several different error messages, however, they are usually caused by invalid/missing Physical IDs. 2D meshes require assigning Physical IDs to all edges as well as the surface representing the domain, whereas in case of 3D meshes, Physical IDs must be assigned to all boundary surfaces and the volume that they enclose. When applying Physical IDs in GMSH, the user must remember that the programme assigns these IDs autonomously, therefore user-defined names mustn't be entered in the dialog box. If the user wishes to change the Physical IDs of the mesh, it is advised to perform this operation within MATLAB, after importing the mesh. For further reference see our YouTube channel where you will find tutorials on meshing in GMSH:

 

QuickerSim CFD Toolbox supports 2 mesh formats: 2binary and 2ascii. It supports only triangular meshes. Quadrilateral meshes are not supported.

Simulating an unsteady simulations requires creating a mass matrix using the assembleMassMatrix() utility and then applying it to the Navier-Stokes equations by means of the addUnsteadyTerms() function. For reference see the following tutorial: TUTORIAL 21

Depending on the modelled heat transfer mechanism, the user has to assemble an addtional transport equation as shown in our tutorial 14.

When a matrix is singular it means that the corresponding system of equations does not have a unique solution. This message is most commonly caused by boundary conditions which:
1. are not defined
2. are inappropriately imposed
3. naturally generate non-unique solutions (as in the standard cavity flow - this is not an error but rather a trait of the case, since the reference pressure level can be chosen arbitrarily).

Contrarily to other commercial CFD software packages, QuickerSim CFD Toolbox for MATLAB assigns outflow boundary conditions to any edges/surfaces to whom boundary conditions haven't been assigned by the user.

The pressure values stored in the solution vector are in fact nodal pressure values divided by the fluid's density ( p / rho , also known as kinematic pressure).

Results can be exported to the .vtk format used e.g. by ParaView by means of the exportToVTK() utility.