Robert Koslover
                                                                                                                                                    Certified Consultant
                                                         
                            
                         
                                                
    
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                                                Posted:
                            
                                2 years ago                            
                            
                                16.04.2024, 12:37 GMT-4                            
                        
                        
                                                    There are a variety of mesh settings available.  If you have adjoining surfaces with different mesh sizes, then Comsol Multiphysics will attempt to connect the meshes smoothly (shrinking elements on the coarser side, at/near the boundary with the finer side).  For a huge difference in mesh sizes, that could take a long while and also can yield poor results, if not managed carefully.  But without seeing what/how you have set up your problem, it is uncertain why your particular meshing process is taking so long.  A problematic geometry can cause an increase in meshing time, while the software attempts to improve the mesh quality.  If you are not already doing so, you should take careful and manual control of the meshing process.  Choose your mesh(es) in detail in accordance with the physics being represented.  If you post your model to the forum, you may get more helpful advice.
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    Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara                                                 
                                                
                            There are a variety of mesh settings available.  If you have adjoining surfaces with different mesh sizes, then Comsol Multiphysics will attempt to connect the meshes smoothly (shrinking elements on the coarser side, at/near the boundary with the finer side).  For a huge difference in mesh sizes, that could take a long while and also can yield poor results, if not managed carefully.  But without seeing what/how you have set up your problem, it is uncertain why your particular meshing process is taking so long.  A problematic geometry can cause an increase in meshing time, while the software attempts to improve the mesh quality.  If you are not already doing so, you should take careful and manual control of the meshing process.  Choose your mesh(es) in detail in accordance with the physics being represented.  If you post your model to the forum, you may get more helpful advice.                        
                                                
                                                                                                            
                                             
                                            
                                                
    
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                                                Posted:
                            
                                2 years ago                            
                            
                                18.04.2024, 07:20 GMT-4                            
                        
                        
                                                    Thanks Robert for your reply. I will describe the model briefly: a steel pipe with size 2.3" (ID) is transmitting a cold fluid (at different rates) the pipe is buried underground and extends for few km's. I want to monitor temperature change of the fluid over time. I took around 10 m solid material aound the pipe to observe how T is changing. Because the flow is turbulent, the mesh in the pipe must be extremely fine and in the solid material is much coarser. I created the mesh myself using mapped mesh in the pipe and trinagular mesh in the solid phase (fine close to the pipe and coarser as it extends far away).
Kind regards,
                                                 
                                                
                            Thanks Robert for your reply. I will describe the model briefly: a steel pipe with size 2.3" (ID) is transmitting a cold fluid (at different rates) the pipe is buried underground and extends for few km's. I want to monitor temperature change of the fluid over time. I took around 10 m solid material aound the pipe to observe how T is changing. Because the flow is turbulent, the mesh in the pipe must be extremely fine and in the solid material is much coarser. I created the mesh myself using mapped mesh in the pipe and trinagular mesh in the solid phase (fine close to the pipe and coarser as it extends far away).
Kind regards,                        
                                                
                                                                                                            
                                             
                                            
                            
                                                                                        
                                Jeff Hiller
                                                                                                                                                    COMSOL Employee
                                                         
                            
                                                                                                                                                
                         
                                                
    
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                                                Posted:
                            
                                2 years ago                            
                            
                                18.04.2024, 08:45 GMT-4                            
                        
                        Updated:
                            
                                2 years ago                            
                            
                                18.04.2024, 08:45 GMT-4                            
                        
                        
                                                    Hello Taofik,
You should consider using the Pipe Flow Module, as this would eliminate the need for a fine mesh in the pipe.
Best,
Jeff
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    Jeff Hiller                                                
 
                                                
                            Hello Taofik,
You should consider using the [Pipe Flow Module](https://www.comsol.com/pipe-flow-module), as this would eliminate the need for a fine mesh in the pipe.
Best,
Jeff                        
                                                
                                                                                                            
                                             
                        
                        
                                                
    
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                                                Posted:
                            
                                2 years ago                            
                            
                                19.04.2024, 05:50 GMT-4                            
                        
                        
                                                    Thanks Jeff for the hint. I'll try it.
Kr, Taofik
                                                 
                                                
                            Thanks Jeff for the hint. I'll try it.
Kr, Taofik