SRS
Scale-Resolving Simulation at Scale
Predicting Vortex Shedding with the Incompressible Cylinder
- Automotive
- Marine
- Energy
What This Simulation Does
The 2d-inc-cylinder example computes incompressible flow past a circular cylinder, producing the classic unsteady von Kármán vortex street in the wake. It is solved with the artificial-compressibility formulation and dual time stepping to recover true incompressible behavior.
- Incompressible Navier–Stokes via artificial compressibility (ζ = 2.5); a pseudo-time pressure evolution enforces the divergence-free constraint
- Bluff-body wake — periodic vortex shedding, the canonical source of unsteady lift, drag, and vortex-induced vibration
- Dual time stepping — physical SDIRK33 with RK45 pseudo-stepping and p-multigrid acceleration for efficient implicit convergence
Key Parameters
- Grid: mixed triangle/quadrilateral mesh around the cylinder, polynomial order 3
- Flow: kinematic viscosity ν = 0.005, inflow Uin = 1.0, reference pressure Pc = 1
- Scheme: Rusanov flux, LDG viscous; dual time stepping with p-multigrid, characteristic Riemann inflow/outflow
- Time: Δt = 0.05, pseudo-Δt = 0.005, tend = 75; residuals logged to residual.csv
The core transferable physics: Flow separates from a bluff body and sheds alternating vortices, driving unsteady forces at a well-defined shedding frequency. This is the root cause of vortex-induced vibration, aeolian tones, and wake buffeting across cars, bridges, risers, and heat exchangers.
What Makes This Capability Unique
True incompressible physics
Artificial compressibility with dual time stepping enforces the divergence-free constraint, recovering genuine incompressible wake dynamics.
Accurate shedding frequency
High-order accuracy captures the Strouhal number and unsteady lift/drag that drive vortex-induced vibration and fatigue.
p-multigrid efficiency
p-multigrid acceleration makes the implicit pseudo-time solve fast, so long-time unsteady wake statistics are affordable.
Mixed-element bluff bodies
Triangle/quad meshing handles arbitrary bluff-body geometry — cylinders, risers, cables, tubes — on unstructured grids.
Domain Applications
Select a domain to see how this simulation applies, with industry-specific scenarios and ROI.
The Problem
Vehicle aerodynamics, cooling-airflow, and wind noise are shaped by bluff-body vortex shedding from mirrors, antennas, A-pillars, and underbody components. Unsteady wakes drive drag, buffeting, and tonal noise that customers hear and regulators measure.
- Mirror and antenna wakes generate aeolian tones and side-glass buffeting — a top NVH complaint.
- Cooling-package and underbody drag from separated wakes directly reduces range/economy.
Aero-driven range/economy and NVH rework are worth tens of millions across a vehicle program.
Applications
| Application | How this simulation maps |
|---|---|
| Mirror wake & wind noise | Vortex shedding frequency predicts aeolian tones and side-glass buffeting |
| Antenna / roof-rack VIV | Shedding-driven vibration predicted from unsteady lift on cylindrical parts |
| Cooling-duct bluff bodies | Wake losses behind heat-exchanger tubes and struts inform cooling drag |
| Underbody component drag | Separated wakes behind cylindrical members quantified for drag reduction |
Quantifiable Business Value
Scenario: An OEM uses vortex-shedding simulation to redesign mirror and antenna shapes, cutting wind-noise rework and shaving drag across a 300,000-unit program.
The drag reduction adds fleet economy/range value that typically exceeds the development savings.
Recommended Next Steps
Validate the shedding frequency
Run the case and confirm the Strouhal number and unsteady lift/drag match the known cylinder benchmark at your Reynolds number.
Sweep Reynolds number
Vary ν and inflow speed to map the shedding-frequency and force response across your operating range.
Apply to your bluff body
Swap in your geometry — mirror, riser, tube, or stack — and evaluate VIV, drag, and suppression options.
Ready to Run This Simulation?
Run this example on SRS's cloud platform. No installation, no infrastructure management — just results.
For questions or to schedule a technical briefing, contact the SRS simulation team.
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