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The paper provides information of fluid-structure interaction (FSI) capabilities in the ANSYS multi-physics software environment for off-shore riser applications. Simulation examples are a simple verification of the FSI code by a bending beam in a flow channel, vortex induced vibrations (VIV) for a cylinder in cross flow and the flow around an experimental riser geometry.

In this paper, the turbulent jet diffusion flame stabilized behind a bluff body (HM1) is simulated using the Flamelet Generated Manifold (FGM) model. Interactions between turbulence and chemistry are detailed in this paper. In HM1 flame, ignition mainly occurs in the outer shear layer while mixing effects dominate in the recirculation zone. Turbulence is modeled by using variants of two-equation Reynolds Averaged Navier Stokes (RANS) models (steady and unsteady RANS), whilst turbulence-chemistry closure is based on FGM approach. Results are compared with experimental data to validate the dynamics and spatial structure of bluff-body flames. Different approaches based on the variants of steady RANS and unsteady RANS are compared for three mesh resolutions. Definitive advantages and disadvantages of each approach are identified on the basis of computational cost and accuracy. The results provide important insights into the simulation of bluff-body flames approaching the blow-off limit.

This work simulates a laboratory-scale 3D methane/air burner, which features a bluff body stabilized, lean partially premixed flame experiencing strong limit cycle oscillations. A thin steel liner is installed around the combustion chamber, which heavily interacts with the flow field and produces large amplitude structural deformation via Fluid-Structure Interactions (FSI). An unsteady RANS approach uses the Shear Stress Transport turbulence model and a Flamelet Generated Manifold combustion model to predict the thermoacoustic oscillations in the turbulent reacting flow. The solver also has a built-in finite element Structure Model, which solves the structural governing equations simultaneously with the CFD-computed, finite volume flow equations. This way, a fully coupled, two-way FSI simulation can be performed to predict the thermoacoustic instabilities and the associated solid deformations in the burner. Overall, the predicted strongest pressure oscillation and wall displacement modes (frequency and amplitude) are all in good agreement with the experimental data across different operating conditions. The established workflow may support realistic gas turbine combustor design and prognosis.