Module 3 capstone
A Verified PDE Simulation
From grids and finite differences to a full simulation with stability analysis and verification.
§ Project brief
The Module 3 capstone is a complete finite-difference simulation of a one-dimensional partial differential equation. You will choose a problem, specify the domain and boundary conditions, implement the FTCS scheme, verify against an analytical solution on a tractable case, demonstrate the CFL stability restriction, and report the results with a claim-support statement.
The capstone draws on every skill of the module: grid construction, finite-difference stencils, boundary-condition handling, explicit scheme implementation, stability analysis, and convergence study.
Verification is the standard
The measure of success is not the visual appearance of the solution but the quantitative agreement with the analytical reference and the correct scaling of the error.
§ Learning outcomes addressed
This capstone assesses
- Construct a spatial and temporal grid for a PDE problem.
- Derive and implement finite-difference stencils.
- Handle Dirichlet, Neumann, and Robin boundary conditions.
- Implement the FTCS scheme for the heat equation.
- Verify against an analytical solution and confirm the observed order.
- Demonstrate the CFL stability restriction.
- Report the results with a claim-support statement.
§ Suggested problems
Heat equation with sine initial condition
u_t = α u_xx on [0, 1], u(0,t) = u(1,t) = 0,
u(x,0) = sin(πx). Analytical solution available.
Rod with one insulated end
Same heat equation, but with a homogeneous Neumann condition
at x = 1. Requires handling a boundary condition
numerically.
Diffusion with Gaussian initial condition
u(x,0) = exp(−100(x − 0.5)²). Analytical solution
available. Tests the grid's ability to resolve a narrow feature.
Wave equation with reflecting ends
u_tt = c² u_xx. Requires two initial conditions.
Different stability condition from the heat equation.
§ Deliverables
| Deliverable | Weight | What it should contain |
|---|---|---|
| Problem specification | 10% | PDE, domain, initial condition, boundary conditions, physical interpretation. |
| Grid and stencil design | 15% | Grid dimensions, spacing, diffusion number, chosen time step, and justification. |
| FTCS implementation | 20% | Working spreadsheet or code with the update rule and boundary handling documented. |
| Verification and convergence | 25% | Comparison against the analytical solution. Observed order at three grid refinements. |
| Stability demonstration | 15% |
Numerical evidence of the CFL condition. Instability at
r > 0.5 shown and interpreted.
|
| Technical report | 15% | Three to five pages covering specification, implementation, verification, stability, and limitations. |
§ Milestones
- Choose the problem and state it precisely PDE, domain, initial condition, boundary conditions. One hour.
- Design the grid Choose Δx, Δt, r, and document the stability margin. One hour.
- Implement the FTCS scheme Three-layer spreadsheet or Python code with documented boundary handling. Four hours.
- Verify against the analytical solution Error table at three grid resolutions. Confirm the observed order. Three hours.
- Demonstrate stability Run at r = 0.4 and r = 0.6; plot and interpret the difference. Two hours.
- Write the report Include the claim-support statement and the limitations. Three hours.
§ Rubric
| Criterion | Excellent | Satisfactory | Needs work |
|---|---|---|---|
| Specification | Complete, precise, physically interpreted. | Complete but terse. | Missing one or more elements. |
| Grid design | Stability margin computed; grid resolution justified. | Grid dimensions stated; stability checked. | Stability not checked or grid unjustified. |
| Implementation | Clean, correct, boundary handling documented. | Correct but boundaries handled informally. | Boundary handling incorrect. |
| Verification | Observed order within 10% of theory; error table complete. | Observed order within 25%. | Observed order not reported or does not match. |
| Stability | Numerical demonstration at two diffusion numbers with interpretation. | One demonstration without interpretation. | Stability not demonstrated. |
| Report | Complete, self-contained, with limitations. | Complete but missing limitations. | Incomplete or overclaims. |
§ Common pitfalls
Watch for these
-
Off-by-one in grid dimensions. A domain
divided into
Nintervals hasN+1grid points. - Applying the interior stencil at boundary points. Boundary values are imposed, not computed.
-
Assuming stability without checking
r. Compute the diffusion number before every run. - Claiming convergence without matching the theoretical order. The observed order is the evidence; a visual match is not.
- Confusing numerical error with model error. A verified scheme does not validate the PDE.
§ Submission
What to submit
- A single ZIP archive named
M3-capstone-yourid.zip. - The archive contains the spreadsheet or code, the analytical verification table, the convergence study, the stability demonstration, and the technical report.
- Submit through the course LMS before the deadline listed on the course schedule.