Triangle Cylinder

Introduction

This case reproduces the well-known Sjunnesson bluff-body flame holder experiment: a triangular cross-section bluff body mounted in a rectangular duct, used extensively in the CFD community as a benchmark for turbulence and combustion model validation. The flow separates from the bluff body and forms a pair of shear layers that roll up into a periodic vortex-shedding wake, which then relaxes towards the downstream channel flow.

The result shown here is the isothermal (non-reacting) baseline case.

Results

Mean and RMS streamwise velocity profiles are extracted at three stations downstream of the bluff body, at x/h = 0.375, 1.53 and 3.75, and compared against the LDA measurements of Sjunnesson, Nelsson & Max.

The mean velocity profiles agree well with the experimental data at all three stations, correctly capturing the shear-layer peaks and the growth of the wake as it develops downstream. The turbulence (RMS) profiles reproduce the correct magnitude and the characteristic twin-peak shear-layer structure.

References

• Sjunnesson, A.; Nelsson, C.; Max, E. — LDA measurements of velocities and turbulence in a bluff body stabilized flame