# Dashboard

*The Flow360 dashboard provides real-time monitoring capabilities for CFD simulations, offering  visualization of convergence metrics and aerodynamic coefficients. This document describes the key features and interpretation of the dashboard components.*

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## Nonlinear Residuals Monitor

The nonlinear residuals monitor displays the convergence history of the simulation, presenting both absolute and relative residuals for key flow variables:

- `cont`: Continuity equation residual
- `momx`: X-momentum equation residual
- `momy`: Y-momentum equation residual
- `momz`: Z-momentum equation residual
- `ener`: Energy equation residual
- `nuHat`: Turbulence model - modified viscosity residual (SA exclusive)
- `k`: Turbulence model - turbulence kinetic energy residual (SST exclusive)
- `omega`: Turbulence model - specific dissipation rate residual (SST exclusive)

The residuals are plotted on a logarithmic scale against physical time steps, allowing users to:
- Monitor convergence behavior
- Assess solution stability
- Determine when steady-state has been achieved

### Interpretation Guide

- Decreasing residuals indicate proper convergence
- Oscillatory behavior may suggest physical unsteadiness or numerical issues
- Plateauing residuals might indicate reaching machine precision or solution stagnation

### Interactive Features

- Toggle between absolute and relative non-linear residual views
- Select and deselect individual residuals
- Choose a time range on the bottom bar of the residuals plot
- Save residuals data as an image

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## Forces and Moments

### Lift and Drag Coefficients
- `CL`: Lift coefficient
- `CD`: Drag coefficient

### Force Coefficients in Component Directions
- `CFx`: X-direction force coefficient
- `CFy`: Y-direction force coefficient
- `CFz`: Z-direction force coefficient

### Moment Coefficients
- `CMx`: Rolling moment coefficient
- `CMy`: Pitching moment coefficient
- `CMz`: Yawing moment coefficient

### Statistics

The dashboard provides statistical data for force coefficients, averaged over the last 10% of steps. This feature helps in:
- Determining final converged values
- Assessing solution stability
- Quantifying solution uncertainty
- Making informed decisions about simulation completion

### Time history

Each coefficient is plotted against physical time steps, enabling:
- Real-time monitoring of aerodynamic performance
- Assessment of force and moment convergence
- Identification of periodic behaviors or instabilities
- Verification of expected aerodynamic characteristics

### Interactive Features

- Click on a plot to enlarge it

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<details>
<summary><h3 style="display:inline-block">💡 Tips</h3></summary>

1. **Convergence Assessment**
   - Monitor both residuals and force coefficients
   - Look for at least 3-4 orders of magnitude drop in residuals
   - Verify force coefficient stability

2. **Solution Validation**
   - Compare force coefficients with expected ranges
   - Check for physical consistency in moment coefficients
   - Verify symmetry properties where applicable

3. **Troubleshooting**
   - Use residual behavior to identify numerical issues
   - Monitor force oscillations for physical unsteadiness
   - Cross-reference with mesh quality metrics when necessary 
</details>

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<details>
<summary><h3 style="display:inline-block"> ❓ Frequently Asked Questions</h3></summary>

- **Why are my residuals not decreasing?**  
  > This could be due to several factors, examples include:
  > - Insufficient mesh quality in critical regions
  > - Inappropriate CFL number settings
  > - Physical instabilities in the flow
  > - Incorrect boundary conditions

- **What is considered a "converged" solution?**  
  > A solution is typically considered converged when:
  > - Residuals have dropped by 3-4 orders of magnitude
  > - Force coefficients have stabilized (variations < 0.1%)
  > - The solution behavior matches expected physical trends

- **How do I interpret oscillating force coefficients?**  
  > Oscillating force coefficients may indicate:
  > - Natural flow unsteadiness (e.g., vortex shedding)
  > - Need for time-accurate simulation
  > - Numerical instabilities

  > Check if the frequency of oscillations matches expected physical phenomena.

- **Can I export the dashboard data?**  
  > Yes, you can:
  > - Save residuals plot as image using the download button
  > - Export numerical data in CSV format using the assets window
  > - Use Python API to download simulation results

- **Why do some residuals plateau while others continue decreasing?**  
  > This is common and can occur due to:
  > - Machine precision limitations
  > - Local flow features affecting specific equations

  > As long as force coefficients are stable, this usually isn't concerning.

- **How do I zoom in on a specific time range?**  
  > Use the bottom bar of the residuals plot to:
  > - Click and drag to select a time range
  > - Use the handles to adjust the range
  > - Click to change your range's position

</details>