Understanding CFD Solver Types and Pressure-Velocity Coupling Methods

1. Introduction

• Overview of CFD solvers in ANSYS Fluent
• Importance of solver selection
• Basic principles of numerical solutions

2. Transport Equation Fundamentals A. Momentum Equations

• Derivation from general transport equation
• Velocity components (u, v, w)
• Key challenges:
  • Non-linear convective terms
  • Complex equation coupling

B. Pressure Considerations

• Unique role in momentum equations
• Absence of direct transport equation
• Solution complexities

3. Major Solver Categories

A. Pressure-Based Solver

• Designed for incompressible flows
• Key features:
  • Pressure correction approach
  • Continuity-momentum coupling
  • Low-speed applications

B. Density-Based Solver

• Optimized for compressible flows
• Key features:
  • Density field calculations
  • Equation of state usage
  • High-speed applications

4. Pressure-Velocity Coupling Techniques

A. SIMPLE Algorithm

• Sequential solution method
• Under-relaxation for stability
• Basic coupling approach

B. SIMPLEC Algorithm

• Enhanced SIMPLE version
• Improved convergence
• Complex case handling

C. PISO Algorithm

• Multiple correction steps
• Transient simulation focus
• Enhanced accuracy

D. Coupled Algorithm

• Simultaneous equation solving
• Higher resource requirements
• Faster convergence

This structured overview provides essential knowledge for selecting and implementing appropriate solver types and coupling methods in ANSYS Fluent simulations.