CPCE Mesh Generation & Boundary Conditions Flashcards
6 cards from real CPCE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CPCE Mesh Generation & Boundary Conditions flashcards as text
What is the primary advantage of a structured (hexahedral) mesh over an unstructured (tetrahedral) mesh in CFD?
Answer: It typically yields lower numerical diffusion and higher solver efficiency
Structured hexahedral meshes align with the flow direction, reducing numerical diffusion and improving solver convergence speed compared to unstructured tetrahedral meshes.
What boundary condition is applied at a symmetry plane in a CFD simulation?
Answer: Zero normal velocity and zero normal gradients of all other variables
A symmetry boundary sets the normal velocity component to zero and enforces zero normal gradients of scalar variables, effectively mirroring the flow without resolving the full domain.
What is the purpose of mesh refinement in the boundary layer region of a CFD simulation?
Answer: To accurately resolve large velocity gradients and capture wall shear stress
Boundary layer mesh refinement (small cells near walls) is needed to resolve steep velocity gradients in the viscous sublayer and accurately predict wall shear stress and heat transfer.
In CFD, what does 'mesh skewness' measure and why is it important?
Answer: The deviation of a cell's shape from an ideal equilateral form, affecting solution accuracy
Mesh skewness quantifies how much a cell deviates from an ideal shape; highly skewed cells degrade interpolation accuracy and can cause solver divergence.
What type of boundary condition is a 'velocity inlet' in CFD, and what quantities must typically be specified?
Answer: An inlet condition requiring velocity vector, turbulence intensity, and turbulence length scale
A velocity inlet requires specifying the velocity magnitude and direction, plus turbulence quantities (intensity and length scale or equivalent) to fully define the incoming flow state.
What is a 'conformal mesh' in CFD and why is it preferred over non-conformal interfaces?
Answer: A mesh where node points match exactly at shared boundaries, avoiding interpolation errors at interfaces
A conformal mesh has matching nodes at shared boundaries between mesh regions, eliminating the need for interpolation across the interface and preventing artificial errors at zone connections.