CFD Analysis of the Effect of Frigate Exhaustions on Helicopter Performances during onboard operations

  • Bardera, Rafael (Instituto Nacional de Técnica Aeroespacial)
  • Matias Garcia, Juan Carlos (Instituto Nacional de Técnica Aeroespacial)
  • Barroso, Estela (Instituto Nacional de Técnica Aeroespacial)

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Helicopter recovery maneuvers on frigates can be a challenge for pilots. The aerodynamic interference between the frigate superstructure and the helicopter results in a complex airflow which causes an increase in the pilot’s workload during the operations above the helideck. But the dangers are not just the presence of large areas of turbulent and detached flow. The interaction of the helicopter with the engine exhaust emissions from the frigate can affect pilot visibility and even the aircraft’s performance. These high-temperature emissions coming out of the funnel can cause sudden changes in air density, affecting the performance of the aircraft turbine during the final phase of the maneuver. This paper aims to perform a numerical analysis using Computational Fluid Dynamics (CFD) to quantify the losses of performance that a helicopter may experience operating in the presence of frigate exhaust emissions. The study is performed on a Simplified Frigate Model, under different cases changing velocities and temperatures of the outlet gases, simulating a helicopter recovery maneuver from the stern. The results of the study show that temperatures can rise by up to 8ºC along the recovery path, which is higher than the 2ºC recommendation for the operations of helicopters around maritime structures. The increase in temperatures produces drops in engine performance and helicopter thrust of up to 2.4 %.