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Optimal trajectory planning for flight through microburst wind shears
, Article Aerospace Science and Technology ; Volume 15, Issue 7 , October , 2011 , Pages 567-576 ; 12709638 (ISSN) ; Kiani, M ; Hassanpour, A ; Sharif University of Technology
2011
Abstract
Microburst wind shear is a potential hazard for aviation safety, especially in some crucial phases of flight like take-off and landing. Optimal trajectories could be useful for suitable retrieval of transport aircrafts encountering microburst. These types of trajectories are investigated in this paper for landing phase in two scenarios of escape and landing utilizing the most recent realistic analytical model of the microburst. In this regard, a set of complete six degrees of freedom aircraft's equations of motion is taken in a variation formulation of this problem. This approach is particularly useful for determination of optimal escape or approach trajectories constrained with respect to...
Optimal Trajectory Planning for Flight through Microburst Wind Shears
,
M.Sc. Thesis
Sharif University of Technology
;
Pourtakdoost, Hossein
(Supervisor)
Abstract
An optimal trajectory for flight through Microburst wind shears is designed which minimizes the maximum deviation from desired trajectory With respect to optimal control methods. The suitable performance of airplane retrieval in abort landing and landing phases at microburst encounter is achieved by influence of mentioned design in worse case of wind fluctuation and variation. 3D Vicroy microburst model is selected to investigate its effects on 6 DOF jet engine aircraft EOMs. Above optimal control problem is solved using gradient method of SD . Furthermore, sensitivity of optimal trajectory to lateral and longitudinal location of microburst, microburst parameters, throttle setting and...
Effects of Wind Shear Flow on the Aeroelastic Performance of a Large-Scale Wind Turbine with UBEM
, M.Sc. Thesis Sharif University of Technology ; Ebrahimi, Abbas (Supervisor) ; Taeibi-Rahni, Mohamad (Supervisor) ; Rezaei, Mohamad Mahdi (Co-Supervisor)
Abstract
Study of the structural flexibility of large-scale wind turbine components on aeroelastic performance is important under the existence of critical atmospheric conditions. Prediction and control the critical deformations, identifying maximum local deformation and modeling the forces involved, are required. Aeroelasticity analysis is a suitable method for studying the coupling effects of wind turbine aerodynamics, dynamics and structures. This research has been done by modeling wind turbine components including blades, hub, nacelle and tower, taking into account aerodynamic couplings, dynamics and structures. Considering the large scale of reference wind turbine, nonlinear equations have added...
Impact of Tower Shadow Effect and Wind Shear Effect on Wind Turbine Gearbox
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohammad (Supervisor)
Abstract
Use of renewable energy has already increased significantly. One of the renewable and suitable sources for replacement with fossil fuels is wind energy, especially wind turbines. But the design, construction, installation maintenance and operation of wind turbines are relatively expensive. One of the most expensive parts of a wind turbine is its gearbox. Wind turbines gearbox due to fluctuating loads unexpected is likely to suffer a premature fatigue. The purpose of this project is to calculate some of the oscillating loads applied to the gearbox and then to investigate the effect of these loads on the service life of the gearbox components. Tower shadow effect and wind shear effect are the...
Prediction of local shear stress and heat transfer between internal rotating cylinder and longitudinal cavities on stationary cylinder with various shapes
, Article International Journal of Thermal Sciences ; Volume 138 , 2019 , Pages 512-520 ; 12900729 (ISSN) ; Nakhchi, M. E ; Sharif University of Technology
Elsevier Masson SAS
2019
Abstract
A numerical analysis has been performed to simulate flow structure, heat transfer, and pressure drop of turbulent flow in an annulus with a few longitudinal cavities on the outer stationary cylinder. The cross sections of cavities are rectangular, closed and open trapezoidal shapes. This kind of annular flow is applicable to industries applications such as electrical generators where heat generates in the cavities containing wires, heating of axial compressor rotor drams, rotating heat pipes for cooling of superconducting machines or motor rotor. The governing equations of turbulent flow are solved by using Renormalization group (RNG) k–ε model for Reynolds and Taylor numbers in the range of...