MFDTIME

MFDTIME, DTIME, DTMIN, DTMAX, Carry
Sets time step sizes for an ANSYS Multi-field solver analysis.

Compatible Products: – | – | – | Enterprise | Ent PP | Ent Solver | –

DTIME

Multi-field time step size. If automatic time stepping is being used [see Notes below], DTIME is the starting time step.

DTMIN

Minimum time step. Defaults to DTIME.

DTMAX

Maximum time step. Defaults to DTIME.

Carry

Time step carryover key.

OFF

 — 

Use DTIME as the starting time step for the next restart run (default).

ON

 — 

Use the final time step from the previous run as the starting time step for the next restart run.

Notes

This command specifies time step sizes for an ANSYS Multi-field solver analysis. If either DTMIN or DTMAX is not equal to DTIME, auto time-stepping is turned on for the multi-field loop. ANSYS will automatically adjust the time step size for the next multi-field step between DTMIN and DTMAX, based on the status of the current convergence, the number of target stagger iterations (specified by MFITER), and the actual number of iterations needed to reach convergence at the current time step.

If auto time-stepping is turned off, the time step size must be evenly divisible into the end time (specified by MFTIME) minus the start time (0 for a new analysis or a restart time specified by MFRSTART).

You can use a smaller time step within each ANSYS field analysis. This is called subcycling. Use the DELTIM and AUTOTS commands to subcycle a structural, thermal, or electromagnetic analysis.

This command is also valid in PREP7.

See Multi-field Commands in the Coupled-Field Analysis Guide for a list of all ANSYS Multi-field solver commands and their availability for MFS and MFX analyses.

Distributed ANSYS Restriction This command is not supported in Distributed ANSYS.

Product Restrictions

ANSYS Mechanical allows MFX analyses but not MFS analyses. ANSYS Multiphysics allows both MFS and MFX analyses.

Menu Paths

Main Menu>Preprocessor>Multi-field Set Up>MFS-Single Code>Time Ctrl
Main Menu>Preprocessor>Multi-field Set Up>MFX-ANSYS/CFX>Time Ctrl
Main Menu>Solution>Multi-field Set Up>MFS-Single Code>Time Ctrl
Main Menu>Solution>Multi-field Set Up>MFX-ANSYS/CFX>Time Ctrl

Release 18.2 - © ANSYS, Inc. All rights reserved.