For most people, CFD is about continuity and Navier-Stokes equations. But this is not always true.
One of the alternatives for CFD simulation is the lattice Boltzmann equation (LBE), where the fluid is treated as fictitious mesoscopic particles (not molecules). If you need something to make you sleepy, please read the short (and concise, and free) book: A Practical Introduction to the Lattice Boltzmann Method.
But for commercial CFD code, most are based on Navier-Stokes equations, and differ in the numerical method: finite volume, or finite element, or a hybrid of both. Finite difference based CFD is hard to find in commercial codes.
When Exa hit the market with the first commercial LBE based CFD code, PowerFlow, about 15 years ago, not so much buzz was created in CFD market. Actually, the first a few releases got not-so-good reviews, partially due to the marketing and sales issues (over-promising). Of course, apparently, in recent years, they got a lot of improvements in both solver and marketing. They also got a few big customers in the automotive industry. But it is still not considered as the mainstream CFD software among CFD practitioners. In the academic circle, there have been several free, LBE based CFD solvers circulating around.
- Not N-S equations based. This differs it from major or mainstream CFD codes.
- Mesh-less (mesh-free).
- Marketed by MSC. This gives it a significant exposure. (Why didn’t MSC acquire it?)
There are some obvious advantages of LBE approach:
- Intrinsic linear scalability in parallel computing, because the collisions are calculated locally.
- Geometric complexity is not a challenge. This includes the solid moving and domain deformation.
- Efficient inter-phase interaction handling for multiphase flow because phase interaction is inherently included in the particle collisions.
Of course, there are some apparent disadvantages of LBE approach:
- Computationally expensive.
- Turbulence modelling.
- Inherently unsteady (transient) simulations only.
As for accuracy, the claim of better accuracy of LBE approach is only theoretically, and probably, correct. In reality, N-S equations approach is still the most reliable one, due to its maturity. Anyway, the accuracy depends on 1). The physical problem; 2). The numerical implementation; 3). Models/correlation used. LBE approach itself will not give you more accurate results. It is up to the software implementation, and the user(usage).
Therefore, it is too early to say the lattice Boltzmann will change the landscape of CFD market. LBE approach still needs time to prove itself, needs more validation cases. Some big players will still adopt the wait-and-see strategy as in any other industry. But it is possible that some will be considering whether they will invest in this area.