CFD prediction of air flow past a full helicopter configuration

Abstract

The present study is one of the first attempts to exploit the GOAHEAD data base to perform a code-tocode evaluation on complete helicopter aerodynamics. The numerical results of two GOAHEAD partners, the German Aerospace Center (DLR) and Politecnico di Milano (PoliMi) are presented and compared to experimental measurements. The study also addresses an evaluation of two different approaches to predict helicopter flows. The first, applied by DLR, accounts for rotor trim and elastic effects by weak fluid-structure coupling. The PoliMi approach, on the other hand, enforces a prescribed kinematics, taken directly from the experiment, on a rigid blade. The simulations refer to a complete helicopter windtunnel model, featuring a scaled NH90 fuselage, the ONERA 7AD main rotor, a scaled BO105 tail rotor, a rotor hub and a pylon, all located inside the 8 m × 6 m test section of the DNW low-speed wind tunnel. The flight conditions correspond to cruise flight at Ma = 0.204 and fuselage attitude α = −2.5 •. The comparisons demonstrate the capability of present unsteady RANS solvers to predict flow fields around complete helicopters.

Fire evacuation in high-rise buildings: a review of human behaviour and modelling research

“…the use of helicopters for evacuation (See Alternative means of escape section) and the additional occupants' effort required to climb stairs. This strategy is currently rarely adopted systematically for three main reasons, namely (1) air turbulence generated by the helicopters together with the smoke and heat coming from the building increase the risk of performing unsuccessful landing and rescue operations (Biava et al 2012), (2) the number of people that can be rescued through this strategy is rather limited if compared with the population of a high-rise building, (3) mobility issues linked to fatigue, people with disabilities, etc. would be worsened by the process of evacuating the building upwards (Shi et al 2009).…”

“…Nevertheless, helicopter rescue procedures are extremely dangerous and there are no standards in the U.S. and in most countries outside the U.S. about their implementation. The landing procedures and the rescue operations are in this case very dangerous due to the air turbulence (Biava et al 2012) and updrafts caused by smoke and heat.…”

Reliability Testing and Failure Analysis for Spar Structure of Helicopter Rotor Blade

“…Some recent studies have been made on aerodynamic performance and mechanical characteristics of helicopters by finite element analysis of the various components [4] and CFD analyses [5,6] on the entire aircraft.…”

Deformable Overset Grid for Multibody Unsteady Flow Simulation

“…The overset grid method was firstly proposed by Steger [21] and subsequently extended by Nakahashi et al [22] for its applications on unstructured grids. The overset grid can be applied to store separation, turbomachinery [23], rotary aircrafts [24,25] and flapping wing aerodynamics [26,27]. For problems with boundary deformation, Fast and Henshaw [28] applied the overset grid in conjunction with a hyperbolic grid generator.…”