Webinar: Gearbox and Engine CFD Analysis of Oil Splashing, Aeration and Sloshing Using Particle Methods
Why is MPS better for gearboxes and engines?
In fact, when one compares computational effort of Finite Volume (FV) to particle methods on a “per time step“ basis – particle methods are more computationally expensive for equivalent numbers of particles/elements, as it needs to perform a search algorithm to identify neighboring particles. A typical FV code won’t perform the roughly analogous remeshing operation every time step. However, there are several differences - particle methods, especially MPS, require far fewer nodes than FV, are tolerant to larger time steps, and are extremely easy to parallelize, which is not necessarily the case for FV algorithms. With the rise of parallel programming and especially scientific programming on GPU’s, this method was able to overtake FV in terms of performance for a number of problems.
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If you require a case with no or little moving parts, where you have the need to resolve large scale differences or have very complex inlet/outlet boundary conditions, you should use FV or a Finite Element (FE) code. If you have a complex moving geometry in an enclosure (e.g. a gearbox), the advantage of the MPS method over its more established counterparts is obvious: there are no meshes, no errors introduced due to interface diffusion or scheme corrections and the run times are an order of magnitude shorter. This is not to say that MPS cannot do other problems, or that FV cannot do gearboxes – it is just that MPS is not the best choice in the first case and FV is definitely not a good choice in the second case.
What are Particle Methods for CFD?
First, particle methods for CFD are for the study of fluids, not the study of particles like sand. Particle methods study the flow of fluid using points in space 'particles' as the calculation points.
Particles can be viewed as objects carrying a physical property of the flow that is being simulated through the solution of Ordinary Differential Equations (ODE) that determine the trajectories and the evolution of the properties carried by the particles.