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So how accurate is SOLIDWORKS Flow Simulation?

Tuesday October 10, 2017 at 11:28am
Applications Engineer Chris Boyles explores the accuracy of SOLIDWORKS Simulation. 

Previously we have had a look at the accuracy of SOLIDWORKSSimulation and now we are going to have a look at Flow Simulation. Unlike Simulation, Flow Simulation doesn’t have any bodies or organisations which run benchmarking tests that have been run against it. Instead, to “Benchmark” Flow Sim SOLIDWORKS have validated the software against test and empirical data for over 20 flow problems. You can have a look at the whole validation document for Flow Simulation in your install directory:

Installation Directory: \Program Files\SOLIDWORKS Corp\SOLIDWORKS Flow Simulation\lang\ english\Docs

We will have a look at a few of them in this blog.

Fluid flow around a circular cylinder is one of the most researched problems in fluid dynamics and SOLIDWORKS Flow Simulation is able to simulate it very accurately. Flow around a cylinder is actually very complicated and its behaviour is very dependent on the Reynold’s number of the Flow; which takes into account the density of the fluid, velocity of the fluid, characteristic length of the body (diameter in this case) and the dynamic viscosity of the fluid. As long as the Reynold’s number of the flow passing over the cylinder is the same as another case, the result should be directly comparable.

The example used in the validation looks at low Reynolds number flows, which produces two steady vortices formed symmetrically behind the cylinder. The image below shows the flow trajectories of result of the FlowSimulation above and an image of such flow below for comparison.

As you can see SOLIDWORKS Flow Simulation is able to correctly predict the vortex shedding at low Reynolds numbers. However, what about high Reynolds numbers? Well if we take a look at the results, we get very close to the empirical data. First we will have a look at the Strouhal number (which is a dimensionless number describing the oscillatory flow mechanisms) of the flow against the Reynolds number.

The blue line is the empirical data and the red triangles are SOLIDWORKS Flow Simulation results. As you can see it is staying accurate to the data spread. We also see a similar trend with the coefficient of drag against Reynold’s number plot.

Again, we see that the results from the SOLIDWORKS FlowSimulation follows the trend of the empirical data accurately, giving you confidence in the results that you can achieve with this package.

If we take a look at another example, Plate Fin Heat Sink Cooling by Forced Convection. The study tested an aluminium heatsink which is heated by a 10 W electrical heater placed on top of a polystyrene block in a wind tunnel and tested at 5 different flow conditions.

The performance of the heat sink is estimated by a thermal resistance defined as:

Where q is the total power input of the heat source (10W).

The 5 different flow cases tested are as follows:

Now if we compare the results of the Flow Simulation study to the experimental data we can see a clear trend in the data where Flow Simulation is correctly able to simulate the forced convection of the heat sink.

In the blog I’ve tried to keep the technicality to a minimum, however if you are interested in the math calculations of the theory shown here, want to have a look at the flow simulation set up files or take a look at all of the other Flow Simulation validation examples have a look at the validation document. The files used along with their set up are located in:

Installation Directory: \Program Files\SOLIDWORKS Corp\SOLIDWORKS Flow Simulation\Validation examples

If you’re interested in the accuracy of SOLIDWORKS Simulation as well, have a look at the blog found here:

'So how accurate is SOLIDWORKS Simulation?'

Chris Boyles

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