Effect of geometric parameters of the bistable fluidic amplifier in the liquid-jet hammer on its threshold flow velocity

• Threshold flow velocities of 33 fluidic amplifiers were studied.
• CFD simulation with dynamic mesh and user-defined function was presented.
• Five representative computational results were validated by laboratory tests.
• Simulated threshold flow velocities agree well with measurements.
• Each geometric parameter has a significant effect on the threshold flow velocity.

The effect of the geometric parameters of the bistable fluidic amplifier in a liquid-jet hammer on its threshold flow velocity was investigated computationally. The flow fields of 33 fluidic amplifiers with different dimensions, each attached to an identical actuating mechanism, were studied to obtain their threshold flow velocities, using Computational Fluid Dynamics (CFD), with the technique of dynamic mesh and a user-defined function. The computational results indicate that each of the geometric parameters has a significant effect on the threshold flow velocity. Five representative computational results were validated by laboratory measurement. The agreement between the simulations and measurements is considered to be quite acceptable. Physical analysis of typical simulation results is also presented.