Assessing The Interaction Of Helicopter Rotor Downwash And Turbulent Airwakes Near Hospital Landing Sites

Abstract

This paper presents an exploratory investigation into the safety implications of helicopter operations at hospital landing sites by analysing the interaction between rotor downwash and the turbulent wakes shed from nearby buildings. The exploratory study has used a steady RANS CFD method to compute the mean air flow in the vicinity of a hospital helipad with a generic helicopter in a 10-foot hover. The main rotor was modelled using a Virtual Blade Model, thereby enabling a coupled solution between the air flow over the buildings and the heli-copter. The study examines the resulting airflow patterns and velocity magnitudes around the site for two different incoming flow directions, with a specific focus on areas where pedestrians are likely to be present. The findings show that, in certain areas, calculated air velocities approach levels considered hazardous, high-lighting the need for careful consideration of helicopter landing sites when being integrated with urban envi-ronments.