Incompressible
ANALYSIS CAPABILITIES AND DOMAINS
Laminar and turbulent flows with/without heat transfer analysis in
internal and external domains can be conducted in 2D, 3D, and
axisymmetric geometries. A choice of linear and higher order finite
elements is available.
EQUATIONS SOLVED
3D-FLUID solves full Navier-Stokes, Continuity, and Energy
equations using the finite element method. In addition, k-E equations
are solved for turbulent flow and streamline upwind method is used
to obtain stable solution at high Reynolds (or Peclet) numbers.
BOUNDARY CONDITIONS
Prescribed flow variable values or their gradients may be applied as
boundary conditions. Spatially periodic boundary conditions can be
applied to analyze flow fields with cyclic symmetry. No-slip boundary
conditions at flow boundaries and at the fluid-solid interface, and the
wall functions for turbulent flow can be included automatically.
SOLUTION TECHNIQUES
A choice of efficient direct (Frontal) and iterative solver is currently
available. Iterative solver is being updated to reflect state-of-the-art
methodology.
HEAT TRANSFER ANALYSIS
- Forced convective heat transfer in the presence of fluid flow in a
weakly coupled analysis
- Free convective heat transfer and fluid flow resulting in a strongly
coupled analysis
- Conduction heat transfer analysis
- Heat transfer due to surface radiation and view factors computed
internally
- Specification of heat flux, convective and radiative boundary
conditions on the domain boundaries
- Heat sources (sinks) specified within the domain
VARIABLE MATERIAL PROPERTIES
Temperature dependent material properties can be given in tabular
and/or polynomial form.
CHOICE OF STEADY STATE OR TRANSIENT ANALYSIS
Transient and steady state analyses can be performed by choosing
time step sizes and relaxation parameters, respectively.
TIME DEPENDENT BOUNDARY CONDITIONS
Time dependent boundary conditions for flow variables can be
prescribed to model truly transient phenomena.
ROTATING FRAME OF REFERENCE
Rotating frame of reference can be invoked to study the fluid flow in
pumps, turbines and other hydraulic machines.
RESTART OPTIONS
The solution can be restarted from the last time step (or iteration) in
transient (or steady) problems. At restarts, the user can change
material properties and/or boundary conditions.
FLUID-SOLID INTERACTION
Fluid-Solid interaction involving
flow and conjugate heat transfer is
available. Pressure loading due to
fluid flow can be applied for stress
analysis in solids. A direct interface
between NISA/3D-FLUID and
NISA II (structures) is also
available.
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| Fluid Structure Interaction |
STREAM FUNCTION AND VORTICITY
Calculation of stream function and vorticity is possible as postprocessed
quantities.
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| Turbulent flow over a car |
MISCELLANEOUS POST-PROCESSING CAPABILITIES
- Mass flow rates and heat transfer rates computed along planes of
flow domains
- Integration of pressure to obtain
drag and lift forces
- Tracking of solid particles in fluid
NON-NEWTONIAN FLUIDS
Non-Newtonian fluids with Power
law and Bingham type fluids can be
modeled. Casson's fluid
characterizing blood flow is also
available.
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| Blood flow through an artery |
FREE SURFACE FLOWS
Flows with free surfaces can be modeled with ALE (Arbitrary
Lagrangian Eulerian) approach
DISTRIBUTED BODY FORCES
Body forces can be included to represent distributed forces due to the
weight of the fluid, chemical, magnetic, and electrical forces.
POTENTIAL FLOW
Velocity potential and stream function formulations are available to
analyze inviscid fluid flow.
SUMMARY OF CAPABILITIES
- Steady state and transient analysis
- 2D, 3D and axisymmetric domains
- Laminar and turbulent analysis
- Non-Newtonian fluids
- Flow through porous media
- Rotating frame of reference
- Free surface flow
- Potential flow
- Boundary conditions
- in global or local coordinate systems
- coupled boundary conditions in global or local coordinate
systems
- time dependent boundary conditions
- temperature dependent boundary conditions
- Temperature dependent material properties
- Conjugate heat transfer analysis
- Forced & mixed and free convective heat transfer
- Surface radiation heat transfer with view factor calculation
- Phase change effects
- Fluid-Structure interaction
- Fluid-Electro-magnetics interaction
- Stress analysis
- Particle tracking
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