FLOW-3D v9.3 - New Features
This new release of FLOW-3D, a computational fluid dynamics software, offers many new solutions for multiphysics simulation needs and advances ease of use and the user’s ability to secure powerful and eye-catching results. The following summary highlights the key new benefits offered in FLOW-3D Version 9.3.
New Modeling Capabilities
Fluid Structure Interaction — Elastic Membranes and Walls
FLOW-3D Version 9.3 enables users to model fluid structure interaction with elastic membranes and elastically-flexing walls. The model simulates the manner in which the small deformations of these types of membranes and walls impact the motion of the adjacent fluid, as well as showing how pressures in the fluid affects the deformations. These fluid structure interactions are fully coupled.
Flexing walls of inkjet
device ejects droplet.
Pre-processor output showing thermally-active layer
in a die casting case.
The unstructured memory allocation technique introduced in FLOW-3D Version 9.2 is a major benefit for users because of its drastic reduction to solver memory and CPU time requirements. However, when the full fluid/solid heat transfer model is needed, the memory savings were effectively lost because all computational cells were required to be “active.” In Version 9.3, a user can define a maximum thermal penetration depth to limit the thermal solution to the volume along the component’s open surface bounded by this depth. Everything outside of this volume is removed from the calculation, resulting in much faster simulations.
Casting users should benefit greatly from this feature. For example, during a die casting filling, heat penetrates the die by only several millimeters and, therefore, solving heat transfer throughout the entire die is unnecessary. If the user defines the thermally-active layer thickness to be, for example, 5 mm, only cells within that layer are retained in the calculation, potentially reducing the total number of cells in the model several fold.
3D view of residue formed from toluene after drying
The formation of residue from dried liquid drops has interest for many engineers, such as for coating processes, formation of pixel arrays of organic materials for video displays and for a variety of micro-electro-mechanical (MEMS) devices. A new residue model in Version 9.3 allows users to model the formation of a solid residue during the drying process (i.e. the "coffee ring" effect) and investigate the influence of such parameters as the initial solute concentration, fluid viscosity, volatility of the solvent, evaporation rate, surface tension and initial shape of the drop.
Two-Component Compressible Gas with Evaporation/Condensation
FLOW-3D’s two-fluid, liquid/vapor phase change model has been extended to include a non-condensable gas component, allowing the users to describe, for example, a system consisting of liquid and gaseous hydrogen and an inert gas such as helium.
The model is more fully described in the Development Note: Non-Condensable Gas Model: Enhancement of the Phase Change Model.
The new non-condensable gas component model is an enhancement to the two-fluid model
which allows for the prediction of gas mixed with vapor phase.
Fluid Structure Interaction — Moving Object Assemblies
The fluid structure interaction capabilities for the General Moving Object model have been expanding with every release as the model matures. The latest major addition is the ability to characterize moving components made of several materials by their density. This new capability will allow users to model coupled motion of multi-material bodies.
Density distribution for ship in animation.
Ship with uneven density distribution.
Boundary Conditions Added/Expanded
Several refinements and additions have been made to the mesh boundary condition models, including:
- Volume flow rate boundary condition
A volume flow rate boundary condition has been added. The flow rate can be defined as a piecewise linear function of time at any of the six mesh boundaries. It can also be combined with fluid height at the four vertical mesh boundaries.
- Linear surface waves
The linear wave boundary condition has been extended to allow for up to a hundred linear wave components to be generated at the same vertical mesh boundary. This addition enables users to define non-linear waves, such as tidal waves, with several Fourier components.
Intensification Pressure for Microporosity Model
An input parameter to define the intensification pressure has been added to the microporosity model. This addition accounts for the external pressure applied to the metal in the die cavity during solidification to reduce porosity.
Drop welding example
Fluid Droplet Sources
A new fluid droplet source has been added in Version 9.3, enabling users to generate spherical fluid droplets at fixed locations and rates. The droplets are emitted with a uniform initial temperature, density, pressure and velocity. Multiple sources, each with its own rate, droplet size and initial conditions can be defined. A source can emit Fluid #1 or #2 in two-fluid problems, as well as bubbles in one-fluid cases. This addition can be employed for instance in droplet coating and droplet welding applications.
Navigator and Workspaces
A new Navigator feature in the FLOW-3D graphical user interface allows users to manage several simulations within the same FLOW-3D session, including building models, running the solver and post-processing results. New Workspaces, containing groups of simulations that may be related to the same project,help the user better organize their work. All simulations in a workspace can be executed sequentially at a click of a button. Simultaneous execution of several simulations is also possible. Multiple Workspaces can be created within a single GUI session.
Runtime Changes to Solver Parameters
It’s not uncommon for users to want to make changes to the numerical settings of a simulation to make it run more accurately and efficiently.
There can be more than one reason to change settings, e.g., poor convergence, a small time-step size, a mentor tip, or just an omission in the model setup. A new Runtime Options tool in Version 9.3 is designed to help in such situations, allowing the user to change most of the numerical options during the simulation without the need to stop or even pause it.
Importing STL geometry into results allows for crisper
STL File Display
With Version 9.3, users who have simulation results where the General Moving Object model was used will now be able to obtain accurate and crisp representation of their moving geometry in 3D plots by importing STL objects.
New Solver Output Options
Many new output quantities have been added to expand the options for users to glean valuable information from their simulations. These include:
- Fluid volume within each porous component
- Electric charge within each component
- Thermal power generated in each component by Joule heating
- Free surface elevation
- Fluid depth
- Froude number
- Distance traveled by fluid
- Fluid viscosity
- Normalized drag coefficient
- Pressure solver relaxation factor OMEGA
- CPU time per time step and per unit time