A study of high lift aerodynamic devices on commercial aircrafts

Aerodynamic performance of aircraft wings vary with flight path conditions and depend on efficiency of high lift systems. In this work, a study on high lift devices and mechanisms that aim to increase maximum lift coefficient and reduce drag on commercial aircraft wings is discussed. Typically, such extensions are provided to main airfoil along span wise direction of wing and can increase lift coefficient by more than 100% during operation. Increasing the no of trailing edge flaps in chord wise direction could result in 100% increment in lift coefficient at a given angle of attack but leading edge slats improve lift by delaying the flow separation near stall angle of attack. Different combinations of trailing edge flaps used by Airbus, Boeing and McDonnel Douglas manufacturers are explained along with kinematic mechanisms to deploy them. The surface pressure distribution for 30P30N airfoil is evaluated using 2D vortex panel method and effects of chord wise boundary layer flow transitions on aerodynamic lift generation is discussed. The results showed better agreements with experiment data for high Reynolds number (9 million) flow conditions near stall angle of attack

Trailing Edge Bluntness Noise Characterization for Horizontal Axis Wind Turbines [HAWT] Blades

Wind turbine noise is becoming a critical issue for many offshore and land-based wind projects. In this work, we analyzed trailing edge bluntness vortex shedding noise source for a land-based turbine of size 2 MW and blade span of 38 m using original Brooks Pope and Marcolini (BPM)and modified BPM noise model. A regression-based curve fitting approach has been implemented to predict the shape function in terms of thickness to chord ratio of aerofoils used for blade. For trailing edge height of 0.1% chord, computations for sound power level were done at wind speed of 8 m/s, 17 RPM. The results showed that present approach for thickness correction predicts the noise peak of ∼78dBA at f ∼ 10 kHz which is ∼15dBA lower than that predicted from original BPM. The results were also validated using experiment data from GE 1.5sle, Siemens 2.3 MW turbines with blade lengths between 78 m and 101 m which agreed within 2% at high frequencies, f > 5 kHz. In addition, results from present approach for trailing edge bluntness noise agreed well with modified BPM by Wei et al. at high frequencies, f ∼ 10 kHz where it becomes dominant. The slope of noise curves from present approach, and modified BPM methods are lower when compared with original BPM

A Computational Design Analysis of UAV’s Rotor Blade in Low-Temperature Conditions for the Defence Applications

This paper discusses about the critical situations faced by the Defence operations with drones in the area of Siachen Glacier in the Himalayas. The reasons for the structural failures in drone’s rotor blades and the low-performance efficiency of the drones at low-temperature conditions are highlighted. A possible solution to the above-mentioned problems has been addressed by introducing a new boundary design in the rotor blades and composite materials. The results which are shown in this paper are obtained by the computational analysis facility located at the Department of Aerospace Engineering, School of Technology, GITAM (Deemed to be University), Hyderabad. By mimicking the Siachen Glacier atmosphere conditions, the proposed rotor blade design has been analysed in CFD

A case study of wind turbine loads and performance using steady-state analysis of BEM

Wind power plants produce energy by utilising the kinetic energy available from wind. Turbine blades undergo millions of revolution during lifetime and subjected to wear and tear due to unsteady aerodynamic forces. In this work, steady-state blade element momentum computations were performed for horizontal axis 2.1 MW wind turbine to evaluate aerodynamic loads and performance. Axial and tangential loads along the blade span were found to increase near the outboard stations of blade but reduced towards tip. Turbine performance parameters viz. thrust and torque coefficients for tip speed ratio range of 5.1–9.5 showed that maximum values are found as 0.95, 0.98 and 0.12, 0.18 for 00 and 100 yaw angles and agreed well with SCADA data used for validation