CFD-FEA Coupled Analysis (Fluid-Structure Interaction)

CFD-FEA coupled analysis computes the aerodynamic, thermal, or multiphase loads on a structure with computational fluid dynamics and applies them to a finite element model, to capture how fluid loads actually deform and stress the part. INNX builds these analyses on OpenFOAM and Code_aster, with custom-coded coupling where commercial pipelines don't reach: transonic flows, combustion environments, injector and turbine geometries. You receive the flow results, the structural response under the real fluid loading, and a report your team can act on.

Typical problems

• A structure sized with simplified or uniform pressure loads, where the real distribution from the flow may move the critical location.
• Aerodynamic loads at transonic speeds, where shocks make the pressure field hard to estimate by hand.
• Combustion chambers, liners, and injectors, where the thermal load sets the stress as much as the pressure does.
• Turbine and injector geometries in which pressure and temperature vary strongly over the part.
• Multiphase flows whose loads on the walls are not available from a standard handbook case.
• A coupling between a CFD code and an FEA code that does not exist off the shelf.

What you receive

• CFD results for the operating conditions agreed in scope: pressure, velocity, and temperature fields, and the loads they put on the walls.
• The fluid loads mapped onto the structural model, with a check that the transferred forces balance the ones computed in the flow.
• Structural FEA results under those loads: stresses, strains, deformations, and the critical locations.
• A written report in the format of the published case studies, covering both the fluid and the structural model.
• Before any work begins, a fixed-scope proposal with clear deliverables, timeline, and price. No open-ended hourly billing.

Methods & tools

CFD with OpenFOAM. Aerodynamic, thermal, and multiphase fluid simulation in OpenFOAM, with in-house-built solvers where the standard ones fall short.

FEA with Code_aster. The structural side is modeled in Code_aster, with element types and solver settings verified against closed-form solutions or published benchmarks, as in the case studies below.

Coupling. When the structure barely deforms, the fluid loads can be computed once and transferred to the structural model. When the deformation changes the flow, the two solutions have to be iterated until they agree. Which approach the problem needs is settled during scoping, before any work is priced. The coupling itself is custom-coded in Python and C where commercial pipelines don't reach.

The work draws on hands-on experience in rocket propulsion, transonic wind tunnel testing, aerospace structural design, turbine combustion chambers and spill-back injectors, and multiphase fluid simulation.

Industries

Aerospace, defense, energy, marine, automotive, and sports equipment: any team building load-bearing composite or metallic structures that need to survive real-world mechanical and fluid loading. For laminated parts, the structural side uses the same checks as the composite laminate analysis.

Typical pricing

Most focused engineering-analysis projects range from $3,000 to $15,000. Complex composite, CFD, optimization and certification-support engagements typically range from $15,000 to $40,000+. Hourly technical support is available from $110/hour.

Final pricing depends on scope, number of load cases, model maturity, reporting requirements and schedule. Every project is quoted as a fixed price before work begins; see the three ways to scope a project.

Related case studies

No coupled CFD-FEA case study is published yet. These Code_aster verification studies show how the structural side is checked and reported:

• Stress Concentration & Hole Edge Verification: Code_aster plate-with-hole verification: peak stress within 1.1% of Peterson's finite-width reference and compressive stress within 4.2% of Kirsch.
• Loaded Pin in a Bore: Frictional Contact Verification: NAFEMS pin-in-bore frictional contact in Code_aster: contact-point displacement within 0.56% (QUAD4) and 0.43% (QUAD8) of the reference.

FAQ