CFD. Turbulence |
Topic 2: Introduction to turbulence
Introduction
Kolmogorov scale
Infeasibility of direct numerical simulation
Turbulence models:
RANS models:
-Reynolds and Favre averages
-Averaged equations. Apparent Reynolds stresses. closure problem
- Boussinesq hypothesis: algebraic models, of one equation and of two equations
- Wall laws. High and low Reynolds number models
- Reynolds apparent stress transport models
LES Models: Description |
Fluid Mechanics II. Ideal flows. Irrotational flows. |
Topic 1: Irrotational movements.
Irrotationality conditions
Irrotational Equations of Motion
Initial and boundary conditions
irrotational movement of liquids
superposition principle
Speed potential at great distances from an obstacle
Irrotational plane motion of liquids: Elementary solutions. Current in nooks and corners. Current around a cylinder with circulation
Two-dimensional irrotational motion of gases
Prandtl–Meyer expansion
Topic 2: Movements with surfaces of discontinuity
Equations for the jump of fluid magnitudes in a discontinuity
Normal and tangential discontinuities
normal shock waves
oblique shock waves
Application: Almost one-dimensional movement of ideal fluids: Critical area. Movement in nozzles. Loading and unloading in warehouses.
Shock waves. Relation of Hugoniot. |
Fluid Mechanics II. Low Reynolds flows |
Topic 4: Movement at low Reynolds numbers
Equations. Initial and boundary conditions
Application to incompressible fluids. Movements around a cylinder and a sphere
Lubrication: Reynolds Equation of Lubrication 3D.
Applications. cylindrical bearing, gas lubrication, rectangular skid, ... |
Fluid Mechanics II. Laboratory practicals |
-Aerodynamic bench test:
boundary layer measurement
- Low speed wind tunnel test
Pressure distribution on blunt body
- Pressure distribution in convergent and convergent-divergent nozzles. Shock waves. sonic blocking |