The fluid flow system provides engineers with a complete analysis system for computational fluid dynamics (CFD), including modeling and visualization systems. It enables you to create 2-D and 3-D models of your designs (or import models from other programs), define flow problems and study the flow characteristics of your design. The fluid flow system can simulate the flow of incompressible substances around obstacles, such as airfoils or within hollow places, such as lid-driven cavities.
The capabilities of the fluid flow system are as follows:
- Newtonian fluids (shear proportional to the viscosity)
- Non-Newtonian fluids (power law and Carreau model)
- Viscous fluids (nonzero friction)
- Incompressible (constant density, generally below Mach 0.3)
- Fully filled volume (flow in equals the flow out of the model, no moving air pockets) or free surfaces
- Isothermal (material properties independent of temperature)
- No mixtures (different fluids can be included in one analysis if they are separate)
- Steady state or unsteady (transient) flow
- 2-D or 3-D models
- Laminar flow with turbulence
- Fast segregated velocity-pressure formulation with velocity correction by mass conservation
- Standard two equation k-epsilon turbulence model and variants with wall roughness
- Automatic turbulence startup
- Fluid flow powered by fan models
- Rotating flow with multiple rotating frames of reference
- Distributed resistance (porous) part combined with regular fluid flow part
- Adaptive solution control for relaxation factors and pre-conditioner options
- Multiple fluid parts for large assembled fluid domain
- Restart from any of previous finished load cases
NoteThe fluid flow method does not guarantee the conservation of mass on an element basis. The mass entering an element may not equal the mass exiting the element. The global conservation of mass is assured by a converged solution. An imbalance due to strong non-linear terms, such as advection terms or inertia terms, may occur due to:
- Turbulence flow
- Rotational flow
- Strong vortex (for example, sudden expansion or flow separation)
- Strong body force (for example, gravity)