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November 2018

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Luma Bendini

Understanding resolution levels for flow simulations with Ingrid Cloud

Solver, iterations and simulation resolution

Besides the price, what is behind the different resolution levels? Easily put: the number of iterations performed during the simulation.

When you sign up and run a simulation with Ingrid Cloud, you will be able to pay as you go. As our CFD tool doesn’t need installation and the simulations are performed in a supercomputing cloud environment, the service is as easy as any pay-per-use solution can be.

The cost of the simulation will depend on the resolution level you choose:


Prototype – medium resolution level. Ideal for early stages of the design process.

Design – high resolution level. Ideal for providing insights on design optimisation.

Validate – very high level resolution. Ideal for validating a case near the end of the design process.

 

Besides the price and behind the different resolution levels there's another important variable: the number of iterations performed during the simulation. What’s an iteration?

To understand an iteration you need to know what happens in a simulation solver – and remember: whatever images you see here are representations of numbers working on a computer to try to solve one of the hardest equations ever discovered, the one that describes turbulent fluid flow.

To calculate the dynamic of the flow, Ingrid Cloud’s numerical solver runs the simulation until the flow field is independent of the initial conditions and a steady flow feature is achieved. After each such simulation is run, the mesh is adaptively refined and a next iteration of the simulation is started. The refinement is based on the estimation of the error and not on the geometry – what makes Ingrid Cloud incredibly efficient and powerful!

The more iterations, the better resolution. The better resolution, the more accurate the simulation is. This sentence is a simplified summary and it doesn’t mean that a professional will always aim for the highest resolution level.

Depending on what the goal of the analysis is, the user will prefer a faster simulation than a more accurate one. When an architect wants to get a feeling of where the main flow is flowing, for example. This professional is more interested in a faster simulation than a high resolution or more detailed analysis at this design stage. Once the project is approved, the architect should run a batch with finer resolution (more iterations) so that it’s ensured that the design is validated and accurate.

So, the key element for choosing the right resolution is knowing what kind of phenomena or output you’re looking for.

Let’s look at the images generated by a simulation – flow visualisation and mesh visualisation – to understand that better.

CFD Simulation Resolution

When the flow first reaches the shape, the uniform behaviour of the flow is not disturbed (red circle). If you’re an engineer interested in the entrance façade of the building (front), a low number of interactions will be enough to provide accurate data, considering that the flow behaviour is not changing much in that area.

But more turbulence happens in the back of the geometry due to flow separation. So, if you’re interested in that area – let’s say for building a playground – you would need a higher resolution level for a better picture about how the wind will behave there. Here you can see how the mesh is refined only where turbulence is great:

CFD Simulation Resolution

Now, if you’re not sure about how a CFD analysis can improve your project – save real time and money – or what kind of data you can receive after a simulation, you can always count on our specialists to take a look in your project.

To check the pricing list for each resolution level: www.ingridcloud.com/product/pricing