CAA Modeling of Helicopter Main Rotor in Hover

In this work rotor aeroacoustics in hover is considered. Farfield observers are used and the nearfield flow parameters are obtained using the in house HMB and commercial Fluent CFD codes (identical hexa-grids are used for both solvers). Farfield noise at a remote observer position is calculated at post processing stage using FW–H solver implemented in Fluent and HMB. The main rotor of the UH-1H helicopter is considered as a test case for comparison to experimental data. The sound pressure level is estimated for different rotor blade collectives and observation angles

Creating a Database of Helicopter Main Rotor Acoustics for Validation of CFD Methods

The work presents recent experiments at the Kazan National Technical University (KNRTU-KAI), related to helicopter acoustics. The objective is to provide a database of near-field experimental data suitable for CFD validation. The obtained set of data corresponds to a Mach-scaled rotor of known planform. An advantage of the current dataset is that direct near-field acoustic data is made available and this allows easy and direct comparisons with CFD predictions, without the need to use far-field aeroacoustic methods

Helicopter Fuselage Drag ─ Combined Computational Fluid Dynamics and Experimental Studies

In this paper, wind tunnel experiments are combined with Computational Fluid Dynamics (CFD) aiming to analyze the aerodynamics of realistic fuselage con¦gurations. A development model of the ANSAT aircraft and an early model of the AKTAI light helicopter were employed. Both models were tested at the subsonic wind tunnel of KNRTU-KAI for a range of Reynolds numbers and pitch and yaw angles. The force balance measurements were complemented by particle image velocimetry (PIV) investigations for the cases where the experimental force measurements showed substantial unsteadiness. The CFD results were found to be in fair agreement with the test data and revealed some §ow separation at the rear of the fuselages. Once con¦dence on the CFD method was established, further modi¦cations were introduced to the ANSAT-like fuselage model to demonstrate drag reduction via small shape changes

Numerical analysis of hovering main rotor aero-acoustic characteristics for ice detection

In this paper, rotors with artificial iced shapes are studied to develop insight in the potential of acoustics-based ice detection. Using the Helicopter Multi-Block CFD solver, approximate iced shapes are added to the blades and the results are analyzed using the FW-H method. Several candidate monitoring positions are assessed for acoustic sensors to be placed on the helicopter fuselage. The influence of ice on the aero-acoustic characteristics of a rotor is calculated, and parameters such as the ice amount and the icing position on the blade are quantified

Acoustic field around a transonic cavity flow

This paper describes new techniques for analysing cavity flows. The beamforming method is used to estimate the pressure fluctuations inside a resonant transonic cavity, highlighting the localisation of the sources of noise. The method produces insightful results and only requires the use of an acoustic array and a mean flow-field. The technique models the noise propagation in a simple and efficient way, applicable for wind tunnel test. In addition, this paper discusses the generation of the cavity tones. Computational fluid dynamics results are analysed using a superposition of reflected acoustic waves driven by the cavity flow. This analysis shows that the time-averaged flow-field drives the frequencies of the tones, while the flow-field fluctuations drive their amplitude. In addition, the tonal dynamics of the cavity flow are represented by a simple model with standing wave oscillations and their modulation. This work is complementary to the well-established Rossiter cavity model

Helicopter Fuselage Optimisation

No abstract available

Helicopter Fuselage Optimisation

No abstract available

Sonderprobleme der Metallbearbeitung mit CO_2-Lasern Lasergerechte Hartlegierungen. Abschlussbericht

Available from TIB Hannover: F93B339+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

CFD simulation of fuselage aerodynamics of the ANSAT helicopter prototype

This paper investigates the aerodynamic lift and drag of the ANSAT helicopter fuselage prototypes using Computational Fluid Dynamics. The CAD model of the fuselage was meshed using an unstructured grid and computed using a viscous flow model under the assumption of steady flow conditions. To account for the influence of the helicopter rotor an actuator disk model was used and the results were compared with computations for the isolated fuselage. The contributions to the total drag of the individual helicopter fuselage components were also studied using different turbulence models. The key components of the fuselage drag were identified