Experimental and numerical investigation on a trimaran airwake, geometry modification

Area of Science:

• Naval Architecture
• Aerodynamics
• Fluid Dynamics

Background:

• Helicopter-ship interaction poses challenges for handling and performance, especially in turbulence.
• Trimaran flight deck design is critical for safe helicopter operations.
• Understanding airflow over flight decks is essential for mitigating aerodynamic risks.

Purpose of the Study:

• To investigate the impact of trimaran flight deck geometry on air pressure distribution.
• To evaluate different top structure designs for minimizing pressure differences.
• To provide insights for optimizing flight deck configurations for helicopter operations.

Main Methods:

• Utilized computational fluid dynamics (CFD) for air pressure analysis.
• Employed Particle Image Velocimetry (PIV) for experimental validation.
• Assessed various geometries under different wind velocities and Reynolds numbers.

Main Results:

• Identified specific geometries (C and F) with reduced pressure differences compared to the base design (A).
• Chamfered edges at 45 and 30 degrees proved effective in minimizing pressure variations.
• Reynolds number effect on pressure was negligible except at the highest value (Re=50e6) and specific locations (x/L=0.5).

Conclusions:

• Flight deck geometry significantly influences air pressure, impacting aerodynamic interactions.
• Optimized trimaran flight deck designs with specific chamfering can enhance safety.
• The study provides a validated approach for aerodynamic analysis of ship flight decks.