Volume mesh and Automated mesh
 

Hi evry1
I am new with CFD and STAR CCM+. When does the volumetric mesh icon must be used.Is it necessary to perform volumetric mesh after Automated mesh is performed.I've used
Surface remesher
tet
prism layer

should i perform volumetric mesh aftr these.

Thank u

I suggest taking a few hours and doing some of the meshing tutorials, this program is really easy to use but its good to run some tutorials still,

thank u. i am learning already.Bu can u tel me whats the difference between volumetric mesh and automated mesh?

the automated mesh contains the surface mesher and volume mesher. the documentation explains it well

thank u. wil luk into tat.
Consider a problem is running attaining convergence.i stop the iteration make some value change(not much).When start the problem to run , the residual values are attaining a very high peak value and continues to converge.Does this affects the result?

Can any1 Suggest a basic book to start CFD.i am supposed to work on Star CCM+ now is it better than Fluent??? If so, in what way? Coz i've used fluent a couple of times the results were much quicker than CCM.
Thank u

For a steady-state simulation, no. For a transient run, possibly - depending on what the result is and what you're interested in.

There are lots of books to 'start' CFD, if you want to learn the basics I would suggest this book:
https://www.amazon.com/Introduction-.../dp/0131274988

The question of 'which code is better' is a matter of opinion and experience and varies from application to application. My experience with both codes is that generally STAR-CCM+ is better. Going from CAD files to a volume mesh is almost always faster and far easier, especially with very complicated geometries. Making changes to a model is easier. The solver is not any faster than Fluent's, though, and Fluent's has more options in terms of discretization schemes and coupling schemes.

Thank you will start from the book

For a flow thru pipe problem
3D,steady,constant density,turbulent,k-epsilon
Wall roughness-0.00004m

Mesh parameter:
Surface remeshr
polyhedrl meshr
prism layer mesher-(hyperbolic tangent-stretch function,20 no.of prism layers,prism layer Near wall thickness-0.00004m)
base size:0.005m

i got pressure drop as 2613 pa from simulation
when i repeat a new simulation with same parameters,i am not getting the same result

Why????:confused:

Multi roughness wall
 

Hi evry1
I am working on a problem of flow through pipe(using water medium).Consider i am having a multi roughness wall.(i.e) two dissimilar materials forming a wall hence their roughness values differs.How do i enter the roughness values separately.Is this even possible?
Its a turbulent flow problem.

perhaps start a new thread for this question, but not really sure do the two different materials (walls) occupy the same space, than you need to use an eq. value, anyways wall roughness parameter is a model, one can have very long discussions on the meaning of parameter.

if you have a flat surface and these two different materials are next to each other than you need to somehow split the surface to get two boundaries so you can define the roughness for each one.

got it
 

Thank u...Yes the surfaces are flat and next to each other in a single pipe.I've split the surfaces as split by patch and gave separate roughness values.

new thread
 

how to post a new thread. i cant find it.:confused:

home > forums > star ccm + : new thread

got it
 

thank you..found it