Tutorial 22: Unstructured Grid Results

1Load and Simulate

Step 1 — Load and Run the Model

Load the unstructured grid model from Tutorial 21: 'Other Tools' → 'LoadModel' → 'Local Model File' (or 'Last Model on Server' if applicable). Then run the simulation: 'Simulation Tools' → 'Simulate' and follow the prompts. The results that appear initially are for the parent (coarse-grid) model only.

2Display Subgrid Results

Step 2 — Overlay Subgrid Results

Go to 'Analysis Tools' → 'Analysis' → 'Display Subgrid Results'. After processing, the subgrid interface appears and refined results are overlaid on the parent model. By default, subgrid results display as black head contours and black velocity vectors — visually distinct from the parent model's colored display.

Subgrid results overlaid on parent model — black contours and vectors show refined subgrid solutions

Step 3 — Clear the Canvas

To focus on subgrids individually, first hide everything:

1. 'Other Tools' → 'ShowOverlay / HideOverlay' — hides the parent model results
2. Click 'Hide All' in the subgrid options interface — hides all subgrid results

You now have a blank canvas. From here, selectively display individual subgrids to examine each refinement zone independently.

Parent results hidden, subgrid results hidden — blank canvas ready for selective display

Step 4 — Display a Single Subgrid

Check the box for 'Sub3' (the refinement zone around the low-K zone and injection well). Click 'Zoom to' — the display automatically frames this subgrid, showing head contours and velocity vectors at the refined resolution. Notice how much more detail is visible compared to the parent grid.

Sub3 results displayed — refinement zone around the low-K zone and injection well, with zoom-to feature

3Customize the Display

Step 5 — Customize Subgrid Rendering

Refine the visualization by adjusting display settings:

1. Check 'Subgrid Scale' — color map uses the subgrid's own head range for maximum local contrast
2. Select 'Sub3' as the Subgrid to draw
3. Choose 'ColorMap and Contour' and change Line Style to 'Dashed'
4. Set maximum velocity vector length to 75
5. Click 'Update Results'

The display updates with the new rendering style — color-filled cells with dashed contour lines and appropriately scaled velocity vectors. The subgrid scale stretches the full color range across the local head variation, revealing detail that would be invisible at the global scale.

Customized display — subgrid scale, color map with dashed contours, adjusted velocity vectors

Step 6 — Zoom Into the Subgrid Detail

Click 'Hide All', then re-check 'Sub3' and click 'Zoom to'. The display cleanly frames the refinement zone with all the customized settings — dashed contours, color-filled cells, and scaled velocity vectors. Observe how the low-K zone deflects flow and how the injection well creates a local mound.

Zoomed view of Sub3 with customized display settings — fine detail around low-K zone and injection well

Step 7 — Switch to Global Scale

Click 'Show All' to display every subgrid simultaneously. Check 'Global Scale' (instead of Subgrid Scale) and click 'Update Results'. All subgrids now use the same color mapping — the parent model's full head range. This unified view lets you see how each refinement zone fits into the regional flow pattern.

All subgrid results shown with global scale — unified color range across all refinement zones

Step 8 — Zoom With Global Scale

Click 'Hide All', re-check 'Sub3', and 'Zoom to' once more. Now the zoomed view uses the global color scale. Compare this to Step 6 — the same subgrid, same data, but different color ranges. The global scale shows how this area relates to the broader model; the subgrid scale shows maximum internal detail. Both views are valid; the question determines which to use.

Zoomed view of Sub3 with global scale — same color range as the parent model for direct comparison

Key Concepts

Multi-resolution interpretation: An unstructured grid model produces results at multiple resolutions simultaneously. The art of interpretation is choosing the right resolution for each question. Regional water balance? Look at the parent grid. Well capture zone? Look at the well subgrid. River-aquifer exchange? Look at the river subgrid. IGW-NET's selective display lets you switch between these perspectives instantly.

Scale affects perception: The same head distribution looks dramatically different at subgrid vs. global color scale. At subgrid scale, a 2-meter head variation fills the entire color spectrum — it looks dramatic. At global scale, the same 2 meters is a subtle shade change within a 20-meter range. Neither is "right" — they answer different questions. Subgrid scale asks "what's happening here?" Global scale asks "how does here compare to everywhere else?"

From results to decisions: The visualization tools in this tutorial aren't decorative — they drive decisions. Seeing the low-K zone deflect flow tells you whether it matters to the overall budget. Seeing the well drawdown at fine resolution tells you whether the capture zone reaches the river. Seeing all subgrids at global scale tells you which features dominate the regional pattern. Each view answers a different management question.

Workflow with Tutorial 21: These two tutorials form a pair — Tutorial 21 builds the model (conceptual features → refinement → grid → simulation), Tutorial 22 interprets the results (parent → subgrids → scales → decisions). The conceptual model drives the grid (Tutorial 21); the grid resolution drives the interpretation (this tutorial). The two are inseparable.

4What's Next

Continue to advanced analysis and 3D modeling capabilities:

Tutorial 23: MODFLOW Analysis Tool — advanced post-processing of MODFLOW output
Tutorial 24: T-PROGS 3D Geologic Model — 3D geology from borehole lithology
Tutorial 25: 3D Flow Visualization — immersive 3D flow fields and water table

This tutorial covers