Altair ultraFluidX 2023.1 Release Notes

New Features

Virtual Fan: ultraFluidX 2023.1 introduces a new virtual fan model. The model allows you to replace a resolved rotating fan geometry by momentum source terms based on a user-defined P-Q curve.; Specifically, you can define a volumetric source region and four coefficients that describe a third-order polynomial reconstruction of the fan’s P-Q curve. The source term applied in this zone is based on an actuator disk model and will represent the induced shift in axial flow velocity. The feature can optionally also update the tangential flow velocity consistently.; The volumetric source regions can have an arbitrary shape as long as they are closed volumes. For internal/HVAC cases, the source zones should be fitted to the cross section of the ducts and the tangential components of the model should be deactivated. To capture local flow phenomena of rotating fans more accurately, the use of disk-shaped source regions and the optional tangential components are recommended.
Far-Field Noise Predictions (Beta): For certain aeroacoustics applications, such as fan noise, HVAC noise and train community noise, you need to evaluate flow-induced noise levels at microphones located far-away from the turbulent regions simulated in ultraFluidX. To support this requirement, sufficient resolution must be added between the source regions and the microphones to accurately propagate acoustic waves with a minimum of dissipation. In some cases, this additional resolution leads to a significant increase of the simulation size and associated computational time. To overcome this limitation, ultraFluidX 2023.1 introduces a far-field noise solution based on the resolution of the Ffowcs Williams - Hawkings (FW-H) analogy. The solution consists in reconstructing the far-field noise levels at any distance from the source regions by processing transient flow information recorded in the source regions. The current capability uses input data recorded on non-rotating physical surfaces (partial surface output) or fictitious surfaces (monitoring surface output) to support the solid and porous FW-H formulations, respectively. This beta version supports an initial implementation submitted as a post-processing step after the ultraFluidX simulation.

Enhancements

Surface Roughness Parameter for Wall Model: ultraFluidX 2023.1 offers to approximate the effect of surface roughness for wheels and belts via additional terms in the wall model.; You can indicate a characteristic roughness height for each wheel/belt instance, which serves to determine a correction term during the calculation of the wall shear stress.
Note: This option is available for the Generalized Law of the Wall (GLW) wall function only.

Resolved Issues

Incorrect merge of H3D files for cases with multiple overset mesh regions into a single overset region has been fixed.