CFD Services
A CFD simulation involves creating a mesh of the geometry, defining a set of representative boundary conditions, running a mathematical simulation on the same and post processing the results to gain an understanding of the physics and characteristics as shown by the simulation. Then relating the results back to reality taking into considerations the limitations of the approximations made.
The generally accepted modeling scenario states that the meshing process accounts for approximately 80% of the total project time when building a hex mesh using classical methods, whilst 95% of all issues involved with solver stability and convergence are related to the mesh. In other words take a short cut at the start of the simulation and pay the price later.
Since we can build high quality hex meshes quickly, and since our simulations run seamlessly on lower cost computers we can concentrate on advanced modeling physics that are not possible with unstructured meshes.
Therefore we can offer a premium CFD service for any level of model complexity.
Our areas of specialty are ->
Engine CFD simulations and design expertise.
By using the Cell3 definition we dynamically change the cell count and smooth the mesh with every time step thus ensuring the best possible cell quality throughout the simulation. This allows us to run a 2.4 million-cell engine model through 720 crank angle degrees on a single CPU core in less than a week. The critical regions of interest in an engine simulation are the number of cells across the valve seat just as the valve opens (minimum of 8 cells), which must quickly increase as the valve opens in order to capture the boundary flow. These valve seat cells in the exhaust must also be only a few degrees away from 90 degrees in order the capture the initial supersonic flow and pressure pulse. We only use LES turbulence models since this produces the most repeatable and accurate results during the intake stroke in terms of simulating tumble and swirl. This is critical when modeling direct injection systems that rely on tumble/swirl patterns for ignition stability.
Aerodynamic Design.
We use LES turbulence modeling in 99% of all our simulations and only ever occasionally use RANS steady state to check for flow gradients with respect to localized mesh density before running the transient simulation. Steady state RANS is not actually a simulation of the boundary layer flow, it is only an approximation method that must be validated and the y+ layers adjusted in order to approach any level of confidence in accuracy. Of course the only other reason to run a RANS steady state simulation is if you cannot run an LES such as is the case with an unstructured mesh.
RTAD RealTime Aerodynamic Design.
RTAD is the next level in real time simulation driven design. Based exclusively on the Cell3 mesh definition, design changes to the simulation model are interactive and occur in real time even for multimillion cell models. Making small changes to the surface of a race car body and seeing results dynamically is only possible if the CFD simulation can resolve these small changes, and this is only possible with a transient LES simulation running on a dynamically smoothed high quality hex mesh. Contact us for more details.
Turbo Machinery.
Precision is the name of the game with turbo machines. We employee continuous meshes throughout the entire model, no sliding or coupled cells anywhere. Instead we use a mesh region stepping method which means we can capture and track turbulent eddies across rows of stator and turbine blades. If you are looking for that extra percent in turbine efficiency why introduce any extra mesh based errors to start with?