10+ Tredence Interview Questions and Answers

Velocity and thermal boundary conditions for outer flow over flat plate and inner flow through pipe.

• Outer flow (flow over flat plate): Velocity boundary condition - free stream velocity parallel to the plate, Thermal boundary condition - constant temperature at the plate surface

• Inner flow (flow through pipe): Velocity boundary condition - parabolic velocity profile, Thermal boundary condition - constant heat flux at the pipe wall

Common turbulent models in CFD include k-epsilon, k-omega, and Large Eddy Simulation (LES).

• k-epsilon model is widely used for industrial applications due to its simplicity and computational efficiency.

• k-omega model is known for its ability to handle adverse pressure gradients and near-wall turbulence.

• Large Eddy Simulation (LES) is used for resolving large-scale turbulent structures in high Reynolds number flows.

• Reynolds-Averaged Navier-Stokes (RANS) models are also commonly u...read more

Aerodynamic refers to the study of the motion of air and other gases, while hydrodynamic refers to the study of the motion of liquids, primarily water.

• Aerodynamics deals with the flow of air around objects, such as airplanes, cars, and buildings.

• Hydrodynamics focuses on the behavior of liquids, including water, in motion, such as in rivers, oceans, and pipes.

• Both fields are crucial in designing efficient vehicles, structures, and systems that interact with air or water.

• Unders...read more

The governing equations solved in CFD include the Navier-Stokes equations, continuity equation, and energy equation.

• Navier-Stokes equations describe the motion of fluid substances.

• Continuity equation ensures mass conservation within the fluid domain.

• Energy equation accounts for the transfer of thermal energy within the fluid.

• Other equations like turbulence models may also be solved depending on the simulation requirements.

The equations governing CFD are based on fundamental laws of physics.

• Based on conservation of mass, momentum, and energy

• Navier-Stokes equations are fundamental in fluid dynamics

• Incompressible flow assumes constant density

• Reynolds-averaged Navier-Stokes (RANS) equations are commonly used

Steady state is when a system's variables do not change over time, while transient state is when variables change with time.

• Steady state: system variables remain constant over time

• Transient state: system variables change with time

• Example: A cup of hot coffee cooling down to room temperature is a transient state process

• Example: A refrigerator maintaining a constant temperature is a steady state process

Boundary layer is the layer of fluid adjacent to a solid surface where the flow velocity changes from zero at the surface to the free stream velocity.

• Boundary layer is a region in a fluid flow where viscous effects are significant.

• It is characterized by a gradual increase in flow velocity from the solid surface to the outer flow.

• The boundary layer thickness depends on the Reynolds number and the surface roughness.

• There are two types of boundary layers: laminar and turbulent.

• B...read more

Mesh dependent test in CFD is a test to determine the sensitivity of the simulation results to changes in the mesh resolution.

• Mesh dependent test involves running the CFD simulation with different mesh resolutions to see how the results vary.

• It helps in assessing the accuracy and reliability of the simulation results based on the mesh quality.

• The test is important to ensure that the simulation results are not heavily influenced by the mesh resolution.

• Common metrics used in me...read more

Relaxation factor in CFD controls the rate at which the solution converges towards the final solution.

• Relaxation factor is a parameter used in iterative methods to control the rate of convergence.

• A higher relaxation factor can speed up convergence but may lead to instability.

• Conversely, a lower relaxation factor can improve stability but may slow down convergence.

• Optimal relaxation factor varies depending on the problem and solver being used.

• Common values for relaxation facto...read more