Dynamic Instability of Spatial Structures under Typical Wind Flow

2011 ◽  
Vol 295-297 ◽  
pp. 1738-1741
Author(s):  
You Qin Huang ◽  
Ji Yang Fu
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Double Layer ◽  
Dynamic Instability ◽  
Wind Flow ◽  
Spatial Structures ◽  
High Wind ◽  
High Wind Speed ◽  
Large Span ◽  
Wind Flows

The mechanism of dynamic instability of large span spatial structures under high wind speed should be studied carefully, but it has seldom been done before. In this paper, a double-layer cylindrical reticulated shell under a typical wind flow is taken as an example to study the dynamic instability of large span spatial structures under wind flows. The interaction of the shell and the flow is ignored and unsteady wind forces on the shell are obtained from wind tunnel tests. The dynamic instability status of the shell is determined by the Budiansky-Roth criterion. The results show that the double-layer cylindrical reticulated shell will become dynamically instable under high wind speed.

scholarly journals BEHAVIOR OF MECHANICALLY ANCHORED WATERPROOFING MEMBRANE EXPOSED TO HIGH WIND SPEED OF WIND TUNNEL

2005 ◽  
Vol 70 (593) ◽  
pp. 17-24 ◽  
Author(s):  
Hirokazu ICHIKAWA ◽  
Michal BARTKO ◽  
Nobuo KATOU ◽  
Hiroyuki MIYAUCHI ◽  
Takanori SASAKI ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
High Wind ◽  
High Wind Speed ◽  
Waterproofing Membrane

scholarly journals Snow fences on slopes at high wind speed: physical modelling in the CSTB cold wind tunnel

2002 ◽  
Vol 2 (3/4) ◽  
pp. 137-145 ◽  
Author(s):  
F. Naaim-Bouvet ◽  
M. Naaim ◽  
J.-L. Michaux
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Physical Modelling ◽  
Experimental Chamber ◽  
High Wind ◽  
High Wind Speed ◽  
Snow Fence ◽  
Snow Fences ◽  
Cold Wind ◽  
Steep Slopes

Abstract. In order to determine the effect of steep slopes on snowdrift generated by snow fences, we have conducted physical modeling experiments in the CSTB (Centre Scientifique et Technique du Bâtiment) cold wind tunnel as part of the European project "Access to Large Facilities". After an overview of previous studies and an accurate description of the drifting snow process inside the experimental chamber,  we present the main results obtained. (1) On flat areas, even for high wind speed, the acknowledged results for moderate wind are still valid: the porous snow fence (50%) is the most efficacious and the bottom gap increases the efficacy of the dense snow fence. (2) The steeper the slope is, the less effective all tested snow fences are. Their effectiveness decreases considerably: the snow catch is approximately divided by two for a slope of 10°. (3) Contrary to flat areas, on steep slopes, the "efficacy" is greater for a dense snow fence.

BEHAVIOR OF MECHANICALLY ANCHORED WATERPROOFING MEMBRANE EXPOSED IN HIGH WIND SPEED OF ACTUAL WIND

2006 ◽  
Vol 71 (610) ◽  
pp. 29-34 ◽  
Author(s):  
Hiroyuki MIYAUCHI ◽  
Nobuo KATO ◽  
Hirokazu ICHIKAWA ◽  
Takanori SASAKI ◽  
Kyoji TANAKA
Keyword(s):  
Wind Speed ◽  
High Wind ◽  
High Wind Speed ◽  
Waterproofing Membrane

Haul-out behaviour and densities of ringed seals (Phoca hispida) in the Barrow Strait area, N.W.T.

1979 ◽  
Vol 57 (10) ◽  
pp. 1985-1997 ◽  
Author(s):  
Kerwin J. Finley
Keyword(s):  
Wind Speed ◽  
Early Morning ◽  
Maximum Density ◽  
Stable Population ◽  
The Sun ◽  
High Wind ◽  
Phoca Hispida ◽  
High Wind Speed ◽  
Ringed Seals ◽  
Calm Weather

Numbers of ringed seals hauled out on the ice began to increase in early June. Numbers on the ice were highest from 0900 to 1500 hours Central Standard Time and lowest (average 40–50% of peak) in early morning. Seals commonly remained on the ice for several hours, and occasionally (during calm weather) for > 48 h. Numbers on the ice were reduced on windy days and possibly also on unusually warm, bright and calm days. Seals tended to face away from the wind (particularly with high wind speed) and oriented broadside to the sun. Seals usually occurred singly (60–70% of all groups) at their holes.Numbers of seals hauled out at Freemans Cove remained relatively constant during June (maximum density 4.86/km2), whereas at Aston Bay numbers increased dramatically to a maximum density of 10.44/km2 in late June. The increase was thought to be due to an influx of seals abandoning unstable ice. The density of seal holes at Freemans Cove (5.92/km2) was much higher than at Aston Bay (2.73/km2). The ratio of holes to the maximum numbers of seals (1.12:1) at Freemans Cove represents a first estimate of this relationship in an apparently stable population.

scholarly journals Evaluation of the AMPS Boundary Layer Simulations on the Ross Ice Shelf, Antarctica, with Unmanned Aircraft Observations

2017 ◽  
Vol 56 (8) ◽  
pp. 2239-2258 ◽  
Author(s):  
Jonathan D. Wille ◽  
David H. Bromwich ◽  
John J. Cassano ◽  
Melissa A. Nigro ◽  
Marian E. Mateling ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Relative Humidity ◽  
High Wind ◽  
Ice Shelf ◽  
High Wind Speed ◽  
Near Surface ◽  
Ross Ice Shelf ◽  
Low Cloud ◽  
The Antarctic

AbstractAccurately predicting moisture and stability in the Antarctic planetary boundary layer (PBL) is essential for low-cloud forecasts, especially when Antarctic forecasters often use relative humidity as a proxy for cloud cover. These forecasters typically rely on the Antarctic Mesoscale Prediction System (AMPS) Polar Weather Research and Forecasting (Polar WRF) Model for high-resolution forecasts. To complement the PBL observations from the 30-m Alexander Tall Tower! (ATT) on the Ross Ice Shelf as discussed in a recent paper by Wille and coworkers, a field campaign was conducted at the ATT site from 13 to 26 January 2014 using Small Unmanned Meteorological Observer (SUMO) aerial systems to collect PBL data. The 3-km-resolution AMPS forecast output is combined with the global European Centre for Medium-Range Weather Forecasts interim reanalysis (ERAI), SUMO flights, and ATT data to describe atmospheric conditions on the Ross Ice Shelf. The SUMO comparison showed that AMPS had an average 2–3 m s−1 high wind speed bias from the near surface to 600 m, which led to excessive mechanical mixing and reduced stability in the PBL. As discussed in previous Polar WRF studies, the Mellor–Yamada–Janjić PBL scheme is likely responsible for the high wind speed bias. The SUMO comparison also showed a near-surface 10–15-percentage-point dry relative humidity bias in AMPS that increased to a 25–30-percentage-point deficit from 200 to 400 m above the surface. A large dry bias at these critical heights for aircraft operations implies poor AMPS low-cloud forecasts. The ERAI showed that the katabatic flow from the Transantarctic Mountains is unrealistically dry in AMPS.

Research on Low-Wind-Speed Wind Power

2013 ◽  
Vol 448-453 ◽  
pp. 1811-1814
Author(s):  
Hai Hui Song ◽  
Jian Jun Wang ◽  
Zhi Hua Hu ◽  
Jin Zhou
Keyword(s):  
Wind Speed ◽  
Wind Power ◽  
Research Development ◽  
High Wind ◽  
Power Development ◽  
High Wind Speed ◽  
Low Wind Speed ◽  
Key Technologies ◽  
Wind Power Development

For high-wind-speed wind power development and problems, propose development and application of low-wind-speed wind power (LWSP). Analysis of the characteristics of LWSP , advantages and necessity of development and application of it. Research the key technologies of LWSP development. It ultimately lay the foundation for research, development and application of LWSP technologies.

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