Highlights of the formulation of the gust effect factor in recent revisions of the wind load provisions in ASCE7-95 are presented. The revised wind map is based on 50-year peak gust speeds in contrast with fastest mile speeds used in ANSI/ASCE7-93. The concepts of spatial and temporal averages are discussed, and the new gust effect factor (GEF) is introduced with its derivation detailed. Exampl...

Based on Navier-Stokes equations and structural and flight dynamic equations of motion, dynamic responses in vertical discrete gust flow perturbation are investigated for a supersonic transport model. A tightly coupled method was developed by the subiteration between aerodynamic equations and dynamic equations of motion. First, under the assumption of rigid-body and single freedom of motion in ...

Let $G$ be a finite and simple graph with edge set $E(G)$. The second geometric-arithmetic index is defined as $GA_2(G)=sum_{uvin E(G)}frac{2sqrt{n_un_v}}{n_u+n_v}$, where $n_u$ denotes the number of vertices in $G$ lying closer to $u$ than to $v$. In this paper we find a sharp upper bound for $GA_2(T)$, where $T$ is tree, in terms of the order and maximum degree o...

Two aspects of vorticity associated with cold pools are addressed. First, tilting of horizontal vortex tubes by the updraft at a gust front has been proposed as a means of getting near-ground rotation and hence a tornado. Theory and a numerical simulation are used to show that this mechanism will not work because warm air parcels approaching the gust front decelerate in strong adverse pressure ...

Two-dimensional electron systems in the presence of a magnetic field support topologically ordered states, in which the coexistence of an insulating bulk with conducting one-dimensional chiral edge states gives rise to the quantum Hall effect. For systems confined by sharp boundaries, theory predicts a unique edge-bulk correspondence, which is central to proposals of quantum Hall-based topologi...

This paper focuses on the development of a wind gust load alleviation control system for implementation in very flexible aircraft. The gust load alleviation system is designed using Linear Quadratic Gaussian (LQG) control techniques, and it is based on a nonlinear model of the coupled rigid-body and elastic modes of a very flexible aircraft. The nonlinear model contains the dynamics of the airc...

Eight papers contributed by the Lincoln Laboratory Weather Sensing Group to the American Meteorological Society’s 16th Conference on Severe Local Storms, to be held October 22-26, 1990 in Kananaskis Provincial Park, Alberta, Canada, are compiled in this volume. The FAA sponsored the summer 1989 field test of the Terminal Doppler Weather Radar (TDWR) system in Kansas City, Missouri to detect win...

Windstorms are a main feature of the European climate and exert strong socioeconomic impacts. Large effort has been made in developing and enhancing models to simulate the intensification of windstorms, resulting footprints, and associated impacts. Simulated wind or gust speeds usually differ from observations, as regional climate models have biases and cannot capture all local effects. An appr...

This paper presents three different schemes for modeling and analyzing the effects of gust fronts resulting from downbursts on structures. These schemes include: (i) the utilization of a manually controlled, pivoted flat plate that can be rotated to a high angle of incidence in a traditional low speed wind tunnel facility to mimic the kinematics and dynamics of a gust front and to quantify thei...