May 12, 2023 at 8:57 amGerhard HolzingerSubscriber
I have a case with transient DPM (unsteady particle tracking using the fluid flow time step) which reports incomplete particle trajectories.
Interaction with the continuous phase is turned off, and the continuous flow fields are not solved for, hence I am using a frozen flow assumption based on a pre-computed flow.
The log reports: number tracked = some number, incomplete = another non-zero number
The warning message says: x% of the total discrete phase mass was not tracked for the expected residence time:
s less on a massweighted average (which is y % of their total age or z % of the last time step).
How does Fluent decide whether a particle trajectory is incomplete?
May 12, 2023 at 10:20 amRobAnsys Employee
Particles go "incomplete" when the number of update steps (set in DPM panel Max steps) is exceeded. This can be due to an excessive flight time, too big a time step or particles that are caught in a small region but change cells very frequently. How high a number are you losing?
May 12, 2023 at 10:34 amGerhard HolzingerSubscriber
It affects only individual particles.
With unsteady tracking, the default for max number of steps is 500.
Does this mean, that for each time step there's a maximum number of 500 integration steps for computing the particle trajectory?
And whenever a particle is reported as incomplete, then it has exceeded this maximum number?
May 12, 2023 at 11:27 amRobAnsys Employee
Pretty much. You can increase the number of steps but it's also a trade off between cpu/time and the odd lost parcel.
- You must be logged in to reply to this topic.
Boost Ansys Fluent Simulations with AWS
Computational Fluid Dynamics (CFD) helps engineers design products in which the flow of fluid components is a significant challenge. These different use cases often require large complex models to solve on a traditional workstation. Click here to join this event to learn how to leverage Ansys Fluids on the cloud, thanks to Ansys Gateway powered by AWS.
Earth Rescue – An Ansys Online Series
The climate crisis is here. But so is the human ingenuity to fight it. Earth Rescue reveals what visionary companies are doing today to engineer radical new ideas in the fight against climate change. Click here to watch the first episode.
Subscribe to the Ansys Blog to get great new content about the power of simulation delivered right to your email on a weekly basis. With content from Ansys experts, partners and customers you will learn about product development advances, thought leadership and trends and tips to better use Ansys tools. Sign up here.
- Suppress Fluent to open with GUI while performing in journal file
- Floating point exception in Fluent
- What are the differences between CFX and Fluent?
- Heat transfer coefficient
- Getting graph and tabular data from result in workbench mechanical
- The solver failed with a non-zero exit code of : 2
- Difference between K-epsilon and K-omega Turbulence Model
- Time Step Size and Courant Number
- Mesh Interfaces in ANSYS FLUENT
- error: Received signal SIGSEGV
© 2023 Copyright ANSYS, Inc. All rights reserved.