Surface pressure survey in a parallel triangular tube array

An experimental parametric study of the surface pressure on a cylinder in the sixth row of a rotated triangular tube array (P/d=1.375) with air cross-flow has been conducted. A range of static displacements were examined. Jet switching was observed in this array and resulted in large asymmetry in the pressure distribution around the static cylinder even in a geometrically symmetric configuration. The large fluctuations in lift force due to jet switching suggest that it should be more seriously considered when designing against failure. The effect of jet switching on the pressure distribution data was mitigated by deconstructing the pressure distribution into two modes. Forces were calculated from the pressure measurements. No simple parameterisation was found for either the lift or drag force, but it was found that the drag force was only weakly affected by the tube displacement. The data set presented here compliments the data previously presented for normal triangular arrays and represents a valuable reference for validation of simulations and flow-induced vibration models.