Results 151 to 160 of about 615 (185)

Optimal paths through downbursts

Guidance, Navigation and Control Conference, 1989
The control of an aircraft's takeoff path through a downburst is presently formulated as a dynamic optimization problem with minimum-altitude constraint and two different performance measures; a landing path through a downburst is also discussed. Paths are determined which, in addition to maximizing an airspeed/altitude combination immediately after ...
Yiyuan Zhao, A. E. Bryson
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The Simulation of Downbursts and its Challenges

Structures 2004, 2004
Numerical simulations are employed to investigate the scale (Reynolds number) dependency and macro-flow dynamics of impinging jets with applications to downburst simulations. It is found that the flow is Reynolds number dependent most probably due to an unstable separation-reattachment near to the wall.
H. Hangan, J.-D. Kim, Z. Xu
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Downburst Recognition Based on a New Watershed Algorithm

2010 International Conference on Machine Vision and Human-machine Interface, 2010
This paper studies the automatic identification of downburst based on the images of Doppler radar with pattern recognition methods from the view of image processing. Together with the characteristics of extreme region corresponding to the downburst in Doppler radar images and the experiences of experts, a new watershed algorithm is proposed based on ...
Yunhong Pan, Zhifang Wu, Yun Zhang, Ling Zhong   +3 more
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A Numerical Study of a Rotating Downburst

Journal of the Atmospheric Sciences, 1993
Abstract Previous studies have revealed that convective storms often contain intense small-scale downdrafts, termed “downbursts,” that are a significant hazard to aviation. These downbursts sometimes possess strong rotation about their vertical axis in the lower and middle levels of the storm, but studies of how this rotation is produced and how it ...
David B. Parsons, Morris L. Weisman
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The DOWNBURST MXO: a real-time downburst monitoring service in eastern Spain

In the framework of the DOWNBURST project, here we present the first real-time downburst monitoring service in eastern Spain. Downbursts are strong winds that descend from a thunderstorm and spread out quickly once they hit the ground. These extreme winds are one of the most damaging natural events and can reach the force and produce damages similar to
Cesar Azorin-Molina, Francisco Granell, Jose Gomez-Reyes, Carlos Calvo-Sancho, Andrés Barrio-Martín, Nuria P. Plaza-Martín, Andreas F. Prein, Sergio M. Vicente-Serrano, Luis Gimeno, Raquel Nieto, Deliang Chen, Tim R. McVicar, Zhenzhong Zeng, Amir Pirooz, Marcos Martínez-Roig, Juan Jesús González-Alemán, María Luisa Martín   +16 more
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Wind Flow Characteristics of a Model Downburst

Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fluid Dynamics of Wind Energy; Bubble, Droplet, and Aerosol Dynamics, 2018
Downburst is an anti-tornado system with a slow rotating column of air slowly descending towards the ground which occurs due to the sudden downfall of air and precipitation generated from the cumulonimbus cloud. This natural event produces a strong downdraft which induces an outburst of damaging winds on or near the ground. This radially divergent wind
Junayed Chowdhury, Jubayer Chowdhury, Dan Parvu, Mohammad Karami, Horia Hangan   +4 more
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Thunderstorm downburst risks to wind farms

Journal of Renewable and Sustainable Energy, 2013
As has been noted in recent experiences, thunderstorms can cause damage to turbine units that are part of a wind farm because of the correlated wind inflow fields that these units can be subjected to simultaneously. We extend a model for simulating thunderstorm downburst events and their effects on a single turbine unit to situations where multiple ...
Hieu Huy Nguyen, Lance Manuel
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A proposed model of the pressure field in a downburst

Wind and Structures, 2013
Pressure field and velocity profiles in a thunderstorm downburst are significantly different from that of an atmospheric boundary layer wind. A model of the pressure field in a downburst is presented in accordance with the experimental and numerical results. Large eddy simulation method is employed to investigate transient pressure field on impingement
Z. Tang, L.Y. Lu
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A unified theory of formation of downbursts and tornadoes

Journal of Wind Engineering and Industrial Aerodynamics, 1990
Abstract A unified theory of the formation of downbursts and tornadoes is formulated that all such natural hazards are caused by the temporal interaction of a cyclone vortex at mid-level with the surface of the earth. The theory is demonstrated numerically by obtaining time-dependent solutions for the Navier-Stokes equations in an initially ...
C.T. Hsu, E. Uzal
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Numerical Simulation of Downburst Wind Loads

2009 International Conference on Management and Service Science, 2009
Wind hazard is the one which has the widespread influence in the nature disaster. Transmission towers have experienced a number of failures due to downburst wind events in recent years, with devastating economical and social consequences. Based on the mechanism of downburst wind load, the present paper proposes an AR model method of adding turbulence ...
Jinwen Wang, Wei-lian Qu
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