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Overview
Getting Started
Core Concepts
Data Storage
Cluster Control
Snapshot
Guide
Convergence plot
File tailing
Use SSH
Whitelist / blacklist
Launch a simulation
Tutorials
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StarCCM+ on Qarnot HPC
Data and Licenses
Configure IP Whitelisting and Port Forwarding to allow Qarnot to access to your self-hosted licenses
Configuring your licence server to use it with Qarnot
Manage your data using rclone cli
Manage your data with a dedicated UI
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Introduction

Simcenter STAR-CCM+ is a powerful multiphysics simulation software developed by Siemens Digital Industries Software This comprehensive tool enables engineers to model and analyze complex engineering problems involving various physical phenomena, including: Fluid flow, Heat transfer, Stress analysis, Particulate flow, Electromagnetics.

This article consists of a general overview of StarCCM+ on Qarnot including useful flags and parameters to use in Tasq.

Tutorials

Interactive demo

In this interactive demo, you will learn how to launch a simple simulation on our bi-Xéon servers using starCCM+

Using the SDK

Follow this tutorial on our blog to learn how to launch starccm+ simulation using our Python SDK

Important flags

This is a non exhaustive list of flags and parameters to consider when using Simcenter STAR-CCM+ on Qarnot cloud HPC Platform

Command Flags for Different Scenarios

When running simulations, various flags are used to optimize execution for different computing environments. Below are examples and detailed explanations of each flag.

Single-Node Execution flags

Command example:

starccm+ -batch mesh,run cylindre_complet_extrusion_both_demi_DP_reconstruit_init.sim -power

Explanation of Flags:

  • -batch
    Executes the simulation in batch mode, meaning it runs without the interactive GUI. This is ideal for automated runs or when using VDI to streamline operations.
    • You can specify several commands at the same time when launching a simulation on star CCM+, or example here we want to execute the meshing and simulation run
    • If you want to just launch your simulation please only use run
    • If you are familiar with StarCCM+ macro, you can use a macro file to start your simulation(<macro-file>.java)
    • If you want to run your simulation step by step for debugging purpose, use step
  • -power
    Enables power or high-performance mode for simulation execution, often optimizing resource usage for intensive computations.
  • mesh,run

Multiple-Nodes Execution flags

Running simulations on multiple nodes allows for parallel processing, significantly reducing computation time for large-scale simulations. By distributing tasks across several machines, you can leverage combined CPU and memory resources effectively. This approach is particularly beneficial when handling complex models that demand extensive computational power.

Command Example:

starccm+ -batch -mpi openmpi -mpiflags "--mca btl ^openib,tcp --mca pml ucx --mca osc ucx" -machinefile /job/mpihosts mesh,run cylindre_complet_extrusion_both_demi_DP_reconstruit_init.sim

Explanation of Flags:

  • -batch
    Similar to the single-node case, this runs the simulation in non-interactive batch mode.
    • You can specify several commands at the same time when launching a simulation on star CCM+, or example here we want to execute the meshing and simulation run
    • If you want to just launch your simulation please only use run
    • If you are familiar with StarCCM+ macro, you can use a macro file to start your simulation(<macro-file>.java)
    • If you want to run your simulation step by step for debugging purpose, use step

The following flags should not be edited as they enabled to run your case on Qarnot's infrastructure

  • -mpi openmpi
    Specifies the MPI (Message Passing Interface) library to use—in this case, OpenMPI—for enabling parallel processing across multiple nodes.
  • -mpiflags
    Allows passing additional options directly to the MPI runtime. The following flags help optimize data transfer between cluster’s nodes and improve performance. You should not need to edit them to use start running your simulation on Qarnot.
    • --mca btl ^openib,tcp: Excludes specific byte transfer layers (e.g.,openib) and enforces the use of TCP.
    • --mca pml ucx: Sets the point-to-point messaging layer to use UCX (Unified Communication X).
    • --mca osc ucx: Configures the one-sided communication for collective operations using UCX.
  • -machinefile
    Specifies a file that contains a list of hostnames or IP addresses of the nodes available for the simulation.
    Usage Tips:
    • Qarnot Scheduler automatically set the IP addresses of the node in/job/mpihosts so you don’t need to edit anything