10+ CFD Analyst Interview Questions and Answers

Turbulence models are used to predict the behavior of turbulent flows by simulating the effects of eddies and vortices.

• Turbulence models are based on the Navier-Stokes equations, which describe the motion of fluids.

• They use statistical methods to simulate the effects of turbulence on the flow.

• There are two main types of turbulence models: Reynolds-averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES).

• RANS models average the turbulent flow over time, while LES models s...read more

RAN, LES, and DNS are different approaches used in computational fluid dynamics (CFD) to model turbulent flows.

• RAN (Reynolds-Averaged Navier-Stokes) models average the flow properties over time, suitable for industrial applications.

• LES (Large Eddy Simulation) resolves large turbulent structures while modeling smaller ones, suitable for complex flows.

• DNS (Direct Numerical Simulation) solves all scales of turbulence without modeling, computationally expensive and used for funda...read more

Steady solver solves for a steady-state solution while transient solver solves for a time-dependent solution.

• Steady solver assumes that the solution does not change with time while transient solver considers the time-dependent behavior of the solution.

• Steady solver is faster and less computationally expensive than transient solver.

• Transient solver is required for problems that involve time-varying boundary conditions or fluid flow behavior.

• Examples of steady solver include Po...read more

Flow models include Eulerian, Lagrangian, Reynolds-averaged Navier-Stokes (RANS), and Large Eddy Simulation (LES).

• Eulerian model: used for steady-state and incompressible flows

• Lagrangian model: used for tracking individual particles or droplets

• RANS model: used for turbulent flows and averaging over time

• LES model: used for resolving large-scale turbulent structures

• Applications include aerodynamics, combustion, and fluid-structure interaction

• Choice of model depends on the probl...read more

Navier-Stokes equation is a fundamental equation in fluid dynamics that describes the motion of fluids.

• It is used to model and predict fluid flow in various applications such as aerodynamics, weather forecasting, and chemical engineering.

• The equation takes into account the conservation of mass, momentum, and energy in a fluid.

• It is a partial differential equation that is notoriously difficult to solve analytically, and requires numerical methods for most practical application...read more

Bernoulli's equation relates pressure, velocity, and height of a fluid in motion.

• Bernoulli's equation is used to analyze fluid flow in various engineering applications.

• It is based on the conservation of energy principle.

• The equation states that as the velocity of a fluid increases, its pressure decreases and vice versa.

• It is commonly used in aerodynamics to design aircraft wings and in hydraulic engineering to design pipelines and pumps.

• Bernoulli's equation assumes that the f...read more

Experience with PowerFlow and ANSYS

• I have extensive experience using PowerFlow for fluid dynamics simulations

• I am proficient in using ANSYS for structural analysis and thermal simulations

• I have successfully integrated PowerFlow and ANSYS for multiphysics simulations

• I have worked on projects where accurate CFD analysis was crucial for design optimization

CFL number is a dimensionless number used in fluid dynamics to determine the stability of a numerical simulation.

• CFL number stands for Courant-Friedrichs-Lewy number.

• It is calculated as the product of the flow velocity, time step, and grid spacing, divided by the fluid kinematic viscosity.

• A CFL number greater than 1 indicates that the simulation is unstable and may lead to inaccurate results.

• A CFL number less than 1 ensures stability and accuracy in the simulation.

Radiation models are used to predict heat transfer through radiation in CFD simulations.

• Radiosity model

• Discrete transfer model

• P1 model

• Rosseland model

• Spectral model