FEM：Finite ElementMethod，有限元技術，擅長於多物理場耦合，流動+溫度+應力。
CFD：Computational FluidDynamics，計算流體力學，擅長於模擬自由表面的流動，處理紊流、飛濺、大自由液面，考慮液體表面張力。
對於C3P Software來說，Cast Designer一開始是以FEM作為主要求解器，提供凝固最佳分析結果搭配基本的流動分析，在大部分的產品上都有很好的準確性。2016年開始，C3P Sofeware Cast Designer將有限元FEM與流體力學CFD完美地結合、透過CFD求解器特有的Volume of Fluid計算技術，能夠提供極為真實的自由液面資訊。2017起許多使用者陸續導入於設計流程，利用CFD求解器獲得更準確的流動結果，精確地模擬出金屬充型過程中氣泡的產生和流動路徑，提供氣孔缺陷的預測帶來更準確的工程判斷。
下方轉錄了Quora討論的內容提供大家參考。
What is the difference between FEA and CFD?
“Most physical phenomenon – be it structural behavior or fluid flow can be described in terms of Partial Differential Equations (PDEs). There are closed-form analytical solutions to these PDEs for simple boundary conditions.
However, in the case of a general boundary conditions, it is not possible to obtain analytical solutions. Atleast this is the case with our today’s knowhow. Alternatively numerical methods are used to solve these equations. Some of the commonly used numerical methods / techniques include
@Finite element method (FEM)
@Boundary element method (BEM)
@Discrete element method (DEM)
@Finite volume method (FVM)
@Finite difference method (FDM)
The first two are more commonly used in structural-related problems; the third for problems that involve particulate behavior; the last two are commonly used in fluid-flow related problems.
Finite Element Method as generally known is what can be actually called a Bubnov-Galerkin approach / method. This is suitable for solving only certain types of PDEs and not everything. For example: Fluid-flow problems are described by Navier-Stokes equations. Due to the presence of advection-convection terms (or first order terms) in this problem, FEM does not perform well in certain conditions. This is the primary reason FEM is not that widely used for fluid-flow problems.
Lately, there have been alternative technique called “Petrov-Galerkin Approach” or even “Petrov Discontinuous Galerkin Methods” that have shown promise towards using the idea of FEM in fluid-flow as well.
Computational Fluid Dynamics (CFD) would related to computational techniques that can be used to solve fluid-flow problems. Here generally FDM or FVM are more commonly used to solve the Navier-Stokes equations due to the above described issue.”