Simulation Setup

This guide walks you through configuring a CFD simulation in Gradient Dynamics Studio. Simulation setup is done in the Simulation tab of a CFD project.

Prerequisites

Before setting up a simulation, you need a mesh. You can:

  1. Generate a mesh in a Meshing project and import it

  2. Use the mesh generated within the same project

  3. Use an existing mesh from a previous project

Setup Overview

A simulation configuration consists of five parts:

  1. Solver family — Automatic, compressible, incompressible, coupled, or transient

  2. Turbulence model — The physics model for turbulent flow

  3. Boundary conditions — What happens at each surface (inlets, outlets, walls)

  4. Solver settings — Accuracy, robustness, and convergence parameters

  5. Run parameters — Maximum iterations, convergence criteria

Step-by-Step Configuration

1. Select Solver Family

Choose the solver family from the dropdown at the top of the Simulation tab. The available options are:

Solver Family

Description

Automatic (recommended)

Studio selects stable defaults from the project physics, mesh, and boundary conditions.

Compressible Flow

Use for high-speed flows, pressure waves, or density changes.

Incompressible Flow

Use for low-speed liquid or gas flows where density variation is not important.

Coupled Multiphysics

Use when flow, heat transfer, and multiple regions interact strongly.

Transient Flow

Use for time-varying wakes, rotating machinery, startup/shutdown, or unsteady thermal response.

Automatic is the best starting point for most projects. Use a specific solver family when your validation target, physics, or project requirements call for it. See Solver Settings for guidance.

2. Select Turbulence Model

Choose the turbulence model from the dropdown. The default is k-ω SST, which works well for most external and internal flow applications.

Available models depend on your subscription tier — see Turbulence Models for details on each model.

3. Set Boundary Conditions

Studio auto-detects boundary types from your surface names:

  • Surfaces named inlet → Velocity inlet

  • Surfaces named outlet → Pressure outlet

  • All other surfaces → Wall (no-slip)

You can override any auto-detected condition. See Boundary Conditions for all available types and parameters.

4. Configure Solver Settings

For most cases, the defaults work well:

  • Accuracy: Standard

  • Robustness: Automatic

  • Convergence target: Application-appropriate residual target

  • Run monitors: Forces, pressure drop, heat flux, temperatures, or other engineering quantities

See Solver Settings for advanced tuning options.

5. Set Run Parameters

Parameter

Description

Typical Value

Max iterations

Maximum solver iterations

500 – 2000

Convergence criterion

Residual threshold for completion

1e-4 – 1e-6

Tip

Start with 500 iterations. If residuals haven’t converged, you can extend the run. Most RANS simulations converge within 300–1000 iterations.

Credit Cost Estimation

Before running, Studio shows the estimated credit cost based on:

  • Mesh size (number of cells)

  • Expected runtime

  • GPU resources required

The estimate is shown when you click Run Simulation, before confirming.

Quick Setup with the AI Assistant

For the fastest setup, use the AI Assistant:

“Set up an external aerodynamics simulation at 30 m/s with k-omega SST”

The assistant will:

  1. Select an appropriate solver family

  2. Select k-ω SST turbulence model

  3. Set inlet velocity to 30 m/s

  4. Configure outlet as pressure outlet (0 Pa)

  5. Apply default solver settings

  6. Ask for your confirmation before running