Monday, December 21, 2015

Static Mixer Simulation

Simulation of Static Mixer

A static mixer is a precision engineered device for the continuous mixing of fluid materials. Normally the fluids to be mixed are liquid, but static mixers can also be used to mix gas streams, disperse gas into liquid or blend immiscible liquids.

Simulation was performed using icoFoam as a transient solver. Geometry and Meshing was done using Salome Meca. A coarse mesh was used for this simulation. Turbulence models have not been implemented , but will be done sooner on an improved simulation. 



Cylinder
Bottom cone 




Extrusion of Bottom conical section for outlet
Inlet faces

Extrusion of Inlet faces
 
Final Geometry of Mixer

Meshing - Tetrahedral meshing using Salome

Velocity Magnitude with Streamlines

Watch the animation here



YouTube link : https://www.youtube.com/watch?v=hHbKx0w35ak

Wednesday, November 4, 2015

OpenFOAM v3.0.0

OpenCFD released the latest version of one of the most widely used open source CFD softwares OpenFOAM v 3.0.0. The new version has been refurbished with addition of new features, fast algorithms, and few structural changes in the software.

Download http://www.openfoam.org/download/source.php

Saturday, October 17, 2015

Trying my hands at SnappyHexMesh ( F1 car simulation )


F1 car - STL file picked from GrabCAD

snappyHexMesh  


Pressure coutour

Velocity Contour

Using OpenFOAM we can easily import stl files and mesh them using snappyHexMesh utility. The stl file used above was taken from GrabCAD ( you can find various CAD files on this site ). I have used simpleFoam here for solving an steady state problem (to save time and energy.. :D ). For more details/discussions you can comment below the post.. Simulation...

Sunday, October 4, 2015

MPI vs. OpenMP

Simple explanation of difference between OpenMP and OpenMPI


"Donald Jones" wrote


OpenMP works on SMP systems, whereas MPI works on both SMP anddistributed memory systems (ie, clusters). The codes we use in our officetypically use MPI between cluster nodes and OpenMP on individual nodes(assuming a dual CPU node), and often both at once (launch on 32 nodeswith 2 CPUs per node; OpenMP spawns appropriate portions of the code overboth CPUs).

From my experience, OpenMP has better performance on SMP systems,ignoring MPI implementations that short circuit the TCP/IP stack (eg,SGI's MPI on Origin 3000s). If you will be launching different runs oneach node, then OpenMP will likely offer better performance than MPI.However, if you are going to launch a single job across multiple nodes,MPI is the de facto standard for parallelizing on clusters.

Other difference between OpenMP and MPI is that OpenMP is a fine grainparallelism and MPI is a course grain parallelism. For example, in OpenMPyou most often parallelize over a loop using compile directives, so thecode runs in serial until the loop, runs the loop in parallel, thenreverts back to serial. Conversely, with MPI the entire code is launchedon each node and you control what each code executes based its nodenumber in the MPI universe along with an algorithm that distributes work,eg, a master/slave model.

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Parallel computing concepts can be really made simple to understand by such explanation for all CS as well as NON-CS users...

P.S : I was reading about OpenMP and OpenMPI and came across a link which had this explanation.

Saturday, October 3, 2015

Monday, September 21, 2015

CFD Engine

You surely need to check this out...really interesting stuff for people who love to work in the field of CFD. I Got in touch with the Blog Writer Robin Knowles and I must say, really liked the way in which he has come up with small articles covering all the aspects of CFD + CAD = CAE overall...now isn't that really cool.. :)

Moving Boundary problem in OpenFOAM

Hey Guys, Its really been a long time since I have posted something. I was looking out for some of my old stuff and found out this ( I had uploaded this on youtube 3 years ago. ). Moving boundary in OpenFOAM. It is based on dynamicInkJetFvMesh mesh motion without solving any flow here. We have used a simple rectangular box here with dimension of (6 x 3 ) with 60 cells in the X-direction and 20 in the Y-direction. Use the solver interDyMFoam to only update mesh with out solving for flow.  ( The original tutorial is developed by Julien Reveillon ).





Till then enjoy and watch out for new stuff.... :)


Saturday, May 23, 2015

Flow over an aircraft using snappyHexMesh

Hi Guys,

Time to work on snappyHexMesh in OpenFOAM. To start with, need to mention about JC Puig whose tutorial I am referring (http://the-foam-house5.webnode.es/) . The tutorial provides a very brief introduction on using snappyHexMesh.

You can find the description of the geometry and mesh on his page. The basic requirements for using a snappyHexMesh in OF are : 

1. Need the geometry STL file, i.e. snappyHexMesh works with a  STerioLithography file which is widely available as an export in CAD softwares.

2. OpenFOAM case file, we can use the available motorBike case in OF to start up with so we need not make much changes to our file structure.

3. Using surfaceFeatureExtract command, to extract the surface feature in the geometry.

4.  creating a blockMesh for external domain

5. snappyHexMeshDict file for setting up the meshing parameters

6. and finally the solver 

Output after snappyHexMesh is used :



7. Solver used : simpleFOAM.

Velocity contour :



Pressure contour :

                             





                  


OpenFOAM v2.4.0 released

Hey Guys,

Check out the new version of OpenFOAM with lots of added improvements like different grading for blockMesh, higher order methods for interface capturing in mutiphase flows, scripts to create MPEG videos from .png images, clone foam cases and lots more. So time to switch to a improved version of OpenFOAM.

Download OF from : http://www.openfoam.org/download/