# Altair AcuSolve 2022.3 Release Notes

## Highlights

- Equivalent Circuit Modeling
- AcuSolve Topology Optimization Smoothing

## New Features

- Equivalent Circuit Modeling
- AcuSolve’s support of battery modeling takes a huge leap forward allowing you to model charge conservation coupled with the energy equation in two different ways for cylindrical-, prismatic-, and pouch-type cells. The battery Joule heating and multi-scale multi-dimensional (MSMD) approaches fundamentally use equivalent circuit modeling (ECM) to characterize the behavior of the electric circuit even in complex electrical systems. Both approaches support first order ECM modeling for maximum simulation speed and efficiency and second order ECM modeling to capture dynamics of the electrical system behavior more accurately. In the battery Joule heating approach, the thermal impact of the electrical system is accounted for in the energy equation and boundary conditions based on current and voltage where the ECM calculates the current and voltage drop through the homogenous cell. With the MSMD approach, a multi-scale modeling of cell and electrochemical scales is used. Thermal effects of the electrical system result from both Joule heating and from the contribution of electrochemical reactions from the ECM sub-model. With either approach you can model charging, discharging, and drive cycle scenarios. The initial states of charge can be set globally or vary locally. Module inputs of power, voltage, current and c-rate may be specified. Electrical inputs can be constant or a function of time or state of charge. Additionally, two standard charging profiles are available; Constant Current/Constant Voltage (CC-CV) where the charging occurs under a specified current load and switches to a constant voltage once full charge has been achieved and Constant Power/Constant Voltage (CP-CV) where the charging occurs under a specified power load and switches to a constant voltage once full charge has been achieved.

## Enhancements

- AcuSolve Topology Optimization Smoothing
- Topology optimization produces smoother shapes than ever before. You may specify a length scale for the smoothing process.
- Inflow on Arbitrarily Surface
- Mass flow inlet conditions are no longer limited to planar surfaces. Cylindrically curved or arbitrarily shaped surfaces can now be used to define inlet mass flow conditions. The flow direction is relative to the local surface normal allowing for inlets on circumferential surfaces.
- Level Set Explicit Re-distancing
- A more direct approach to calculating the fluid interface in immiscible multiphase simulations is now available with the explicit type of levelset re-distancing. Improvements in speed of up to 20% or more are possible on medium complexity models.
- Model Dimensions to Log File
- In addition to the minimum and maximum extents of the model simulated, the Log file now includes the overall dimensions of the resulting bounding box for easy assessment and confirmation of model size.
- Multiplier Function for Distributed Heat Source
- Multiplier functions were previously only available for fixed heat loads, modifying a single value per element set. In this version, the multiplier function is extended to distributed heat sources, allowing you to define spatially varying heat loads that are also optionally time or time step dependent.
- New SimLab-based Tutorial
- One (1) new tutorial is available in the SimLab CFD user interface. The
new tutorial is:
- ACU-T: 3510/SL 2171: Battery Equivalent Circuit Model

- Updated SimLab-based Tutorials
- Two (2) tutorials have been updated for the SimLab CFD user interface.
The tutorials are:
- ACU-T: 3500/SL 2170: Electric Potential – Automotive Fuse
- ACU-T: 7201/SL 2501: Topology Optimization with Flow Distribution

- New SimLab-based Validation Case
- One (1) new validation case is available in the SimLab CFD user
interface. The new validation case is:
- Viscous Heating Inside a Rotating Annulus

## Resolved Issues

- Error strings written to the Log file due to issues with licensing have been enhanced.
- An issue with conjugate heat transfer and Joule heating has been corrected.
- An error related to mass flux inlets with AcuSolve/EDEM bi-directionally coupled simulations has been corrected.
- A condition preventing torque models to be used with AcuSolve/EDEM bi-directional coupling has been addressed and corrected.
- The setup for leveraging EFA on AWS has been corrected.
- The tutorial input file download links for ACU-T:2100 has been fixed.
- The tutorial input file download links for ACU-T:6104, ACU-T:6105, and ACU-T:6106 have been updated.
- Droplet size notation in ACU-T: 4003 tutorial has been corrected.
- Plots and instructions in the Asymmetric Diffuser and Backward-Facing Step validation cases have been corrected.
- Corrections were made to the viscosity model section of the Command Reference Manual regarding the ramping of viscosity with a multiplier function. Typos in the Command Reference Manual for the udfGetMmoRgdData() user function and convergence check parameters were corrected.
- A brace was removed in the multiplier function example for the multiplier function command.
- A colon was replaced by a semicolon in the user-defined function example for the mesh motion command.
- Corrections were made to the surface tension model of the field interaction model in the Command Reference Manual.