共查询到20条相似文献，搜索用时 15 毫秒
1.
V. P. Reutov V. V. Chernov A. B. Ezersky P. R. Gromov 《Izvestiya Atmospheric and Oceanic Physics》2012,48(2):185-192
We present the results of laboratory studies of convective structures in a thin (5 mm) ethyl-alcohol layer blown off by airflow
in a wind tunnel. The formation of structures in the working part of the alcoholfilled cuvette are determined by the destabilizing
(inversion-type) temperature profile arising due to the evaporation of liquid. The design of the experimental setup ensures
the unidirectional character of the current in the working part of the cuvette where structures are formed. We singled out
three stages through which structures successively evolve with increasing the wind velocity: polygonal cells (no blowing),
along-flow elongated cells, and along-flow aligned convective roll structures. The profiles of the average and pulsation velocities
in the boundary layer over the cuvette are determined together with the drift flow velocity of the liquid at different transition
stages from convective cells to rolls. The dimensionless flow parameters are estimated and the comparison of the experimental
data with known theoretical results is fulfilled. 相似文献
2.
A. K. Monzikova V. N. Kudryavtsev A. G. Myasoedov B. Chapron S. S. Zilitinkevich 《Izvestiya Atmospheric and Oceanic Physics》2017,53(1):76-83
In this paper we analyze SAR wind field features, in particular the effects of wind shadowing. These effects represent the dynamics of the internal atmospheric boundary layer, which is formed due to the transition of the air flow arriving from the rough land surface to the “smooth” water surface. In the wind-shadowed area, the flow accelerates, and a surface wind stress increases with fetch. The width of the shadow depends not only on the wind speed and atmospheric boundary layer stratification, but also on geographic features such as windflow multiple transformations over the complex surface land–Lake Chudskoe–land–Gulf of Finland. Measurements showed that, in the area of wind acceleration, the surface stress normalized by an equilibrium value (far from the coast) is a universal function of dimensionless fetch Xf/G. Surface wind stress reaches an equilibrium value at Xf/G ≈ 0.4, which is the scale of the planetary-boundary-layer relaxation. 相似文献
3.
为了改善注水开发效果差的情况,对无因次等孔隙体积配产配注理论改善注水开发效果的方法进行了研究。针对高30断块油藏,分别使用无因次等孔隙体积法和传统的kh值计算其合理配产配注量,接着采用油藏数值模拟进行了无因次等孔隙体积配产配注法和传统的kh法在该断块油藏注水开发的对比预测。结果表明,相比kh法,无因次等孔隙体积法使油田有效开发时间延长27年,采出程度由22．46％提高到27．94％,提高5．48％,增产原油19．88×10^4t。所以采用无因次等孔隙体积配产配注法比传统kh配产配注法更加符合油藏实际,使有效开发年限更长,最终水驱采收率更高。该方法可以为同类注水开发油藏的合理配产配注提供参考。 相似文献
4.
Jen-Men Lo 《Ocean Engineering》1996,23(6):519-531
Laboratory experiments were carried out to test the effectiveness of single floating booms, and series of barriers in preventing oil slick and jellyfish movement under various current, wind, and wave conditions. Samples of Kuwait light crude, Kuwait heavy crude, and emulsified Kuwait heavy crude oil were selected for the test program. It was found that the single floating booms were only effective in preventing the oil slick movement at current speeds less than 0.15 m/s for emulsified oil and 0.25 nits for non-emulsified oil. Double floating booms (with a distance of 16 times the boom's draught between them) prevented both non-emulsified and emulsified oil movement when current speed was less than 0.25 nits. The double floating boom system had the best performance in containing oil slick movement.In the combined air-bubble barrier and floating boom system, the air-bubble plume lifted the jellyfish to the water's surface, and thus most jellyfish accumulated in front of the floating boom. With the help of a proper collection device (such as a suction pump), the accumulated jellyfish could be removed to a desired location. Therefore, the quantity of jellyfish moving into the intake channel was reduced.Based on the test results, three different arrangements were recommended for the protection Kuwait's water intakes and harbors from oil slick and jellyfish movement. 相似文献
5.
以高精度再分析风场为驱动,利用SWAN模式模拟了台风“达维”Damrey（2005）经过北部湾海域时的波浪场。通过与实测的风和波浪实测对比发现,波浪后报结果与实测结果符合较好。文章给出了台风浪期间波高、周期、波长和波向等要素的分布特征,讨论了以台风眼为中心不同海域的波浪方向谱特征。本文最后分析了台风期间实测波浪能谱的变化特征。 相似文献
6.
台风Wayne过后南海北部陆架海域的近惯性振荡 总被引：6，自引：0，他引：6
1986年8月18日8616号台风维纳(Wayne)在南海中部生成,其后在南海北部迂回盘旋,前后3次穿越巴士海峡,9月4日在海南岛登陆。布放在海南岛东部陆架上的锚系浮标记录了台风中心过境前后风和近表层的海流响应。分析结果表明,台风中心过境造成海水强烈的近惯性运动,其影响大约持续了6—8d,近惯性振荡的频率为0.029 2周.h-1(周期约34.2h),高出当地的惯性振荡频率(0.028cph)4.3%。带通滤波所提取的惯性运动特征显示,台风过境后惯性振荡逐渐衰减,惯性圆逐渐向西南方向偏移。根据这一个例,探讨了台风条件下近表层流速与风速的关系以及台风尾迹中近惯性流流速衰减过程的经验描述,可为近海海洋工程设计提供参考。 相似文献
7.
Laboratory experiments on conically shaped oil collectors beneath a marine riser are described. The collection concept involves oil, water and gas entering the collector and being driven into a separating sytem by gas-lift. A parametric study involving various collector shapes, heights above the wellhead, and gas, oil and water flow rates was carried out. The important dimensionless variables were identified and quantified with the conclusion that effective collection is possible if the collector height is sufficiently small and the ratio of water pumped to gas flow is sufficiently large. Increased collector heights can be accommodated at the expense of requiring increased water flows by use of larger diameter risers. The amount of gas required for most efficient oil collection is found to be much less than is expected to come from most blowouts when a single collector and riser system is used. This difficulty can be greatly diminished by the use of a specially designed gas-separating collector which passes most of the gas to the surface through a riser separate from the one which carries the liquids. 相似文献
8.
Tremendous economic loss and environmental damages are caused by oil-spilling accidents in sea. Accurate prediction of the underwater spreading and surface drifting of oil spills is important for the emergency response. In the present study, numerical investigation on the underwater spread and surface drift of oil spilled from a submarine pipeline under the combined action of wave and current was carried out to examine the effects of physical ocean environment, leaking flux and spilled oil density and viscosity. Reynolds-Averaged-Navier-Stokes (RANS) equations, realizable k-ε turbulence model and volume of fluid (VOF) model are employed to describe the multiphase flow, and velocity-boundary wave-making technique combined with the sponge layer damping absorber technique realizes the numerical wave flume. Oil spill experiments were conducted to validate the numerical model. The calculation results indicate that compared with the environmental conditions of still water, only current and only wave, a larger scope of underwater spreading and relatively slower rising rate and relatively faster drifting rate of oil droplets are observed under the combined action of wave and current. The leaking flux affects the floating time and dispersion concentration, while the ocean environment affects the horizontal migration and surface drifting. Under the specific conditions of present work, oil density has obvious effect on the underwater spread but limited effect on the surface drifting, while oil viscosity has little effect on both the two processes. 相似文献
9.
10.
利用修改的一层原始方程模式(Danard模式),对台湾海峡地区地面风场进行了数值试验和数值模拟。首先在一些理想情况下,研究了地面气压场、地形、摩擦和加热对地面风场的影响。指出:地面气压场决定了地面风场的基本分布;摩擦对海陆风速差异有重要作用;地形作用表现为弱的分流和阻流作用,加热作用使风场趋于紊乱。并在东北气流控制下的实际风场进行了数值模拟,效果良好。 相似文献
11.
当FPSO服役于目标油田时,将受到风浪流的作用力。其中,风力给FPSO一个恒定的静力,使其偏离原来的位置。风力计算在FPSO系泊系统的分析过程中是非常重要的。设计人员常常参考OCIMF进行风力计算,或者参考API规范得出。OCIMF为针对油轮的计算规范,但使用OCIMF计算FPSO风力及流力的方法,与FPSO的适应性仍需要进一步论证。API规范针对海上浮式系统,其计算风流力的方法使用也非常广泛,其原理为将FPSO上部各个模块风力叠加得出。以FPSO风载荷为研究对象,开展了风洞模型试验,获得了典型FPSO风载荷特性曲线,并将试验结果分别与OCIMF结果和API规范计算结果进行对比分析,最终给出FPSO风力计算方法的建议。本数据可用于FPSO的风力计算,也可为FPSO运动、系泊的设计研究提供参考。 相似文献
12.
Surface Velocity Program drifters drogued at 15 m depth were deployed in the Taiwan Strait (TS) and Luzon Strait in 2005 and
2006. Several drifters in the TS and the Pacific were fortuitously overrun by the typhoon Hai-Tang (July 2005) and Shan-Shan
(September 2006), respectively. The drifter and QuikSCAT wind data clearly demonstrate that the surface current over the TS
and the Pacific can change dramatically for a period of about two days due to the strong winds of a typhoon during its passage.
Our results show that the area of storm-affected surface currents is considerably smaller for a weaker typhoon (category 2
Shan-Shan), about 300∼400 km in radius, than for a stronger typhoon (category 5 Hai-Tang), about 800 km in radius. The maximum
observed current speed in the TS was 1.7 ms−1 (or 2.2 ms−1 in net speed change) under the influence of Hai-Tang, and 2 ms−1 in the Pacific under the influence of Shan-Shan. Drifter observations revealed the unusual phenomenon of flow reversal in
the surface layer of TS and the Kuroshio induced by the typhoon passage. The effect of a typhoon on surface flows is amplified
by the long, narrow geometry of the TS. Surface currents generated by wind forcing along the passage of a traveling typhoon
can be explained by the Ekman drift. 相似文献
13.
A. S. Kholodov M. O. Vasil’ev E. A. Molokov 《Izvestiya Atmospheric and Oceanic Physics》2011,47(1):87-107
The earlier developed monotonous conservative variant of a net-characteristic method of the second- and third-order approximation based on 3D equations of magnetic gasodynamics with consideration for the magnetic field diffusion is expanded for the solution of dynamic problems on the flow of the upper atmosphere of the Earth by solar plasma. It is modified, which results in support for the solenoidality of the magnetic field and the removal of the magnetic charge. Calculations are carried out and preliminary results of using software complexes to simulate the passage of the leading edge of solar plasma through the upper atmosphere of the Earth are given. Unlike existing studies in this direction, the dynamics of the passage of the leading edge upon a strong burst in the intensity of solar wind over the entire altitude range from the surface of the Earth to the upper magnetosphere is considered. 相似文献
14.
Masahiro Endoh 《Journal of Oceanography》1973,29(1):28-43
Response of the barotropic western boundary current to typhoon passage is investigated by the use of the numerical models described in Part I. Steady states obtained in Part I are chosen as the initial conditions for undisturbed currents. In these models it is assumed that an axially symmetric typhoon (radius = 100 km, maximum wind speed = 27.4 m/sec) moves parallel to the western boundary.For the model with a flat bottom the boundary flow diminishes its strength and broadens its width after the passage of the typhoon offshore. For the model with a continental slope the effect of the typhoon is significantly different depending on the distance of the path of the typhoon from the western boundary. Specifically the north wind on the continental slope causes the formation of cyclonic vortex, which progresses southwards along the slope in the northern hemisphere. Linear theory of continental shelf waves indicates that the phase speed of the propagation of the vortex is 2.4 m/sec. Anomalies of the water level along the coast are also calculated from geostrophic relationships. 相似文献
15.
M. Paul Mosley 《新西兰海洋与淡水研究杂志》2013,47(3-4):351-357
Riffles and points of divergence of branch channels in braided rivers are critical controls upon passage of fish and recreational boats because they are points at which depths are at a minimum. Depths on randomly selected riffles were measured in braided reaches of the Ashley, Hurunui, and Rakaia Rivers and related to discharge; minimum depths encountered in extended reaches of these rivers at a range of flows have also been measured. The data can be used to predict minimum available passage depths at a specified flow, or conversely, to predict the discharge required to maintain a specified minimum passage depth. However, presently available estimates of critical minimum depths required for various instream uses (migration of salmonids, jetboating) appear excessively conservative, and minimum depth requirements must be more accurately determined before instream flow needs can be properly assessed. 相似文献
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17.
利用三维斜压流体动力学模型 ,通过对东海沿岸海区冬、夏季的斜压环流及其温盐结构的数值研究 ,揭示研究海区垂直环流及其温盐结构的动力过程及其成因。垂直环流的模拟结果表明 :冬季 ,沿岸海区的垂直环流以逆时针流动 ,近表层为向岸流 ,沿岸为下降流 ,近表层以下为离岸流 ,其在外海有明显的上升趋势 ,沿岸下降流自表层至底层逐渐由强变弱 ;夏季 ,沿岸海区的垂直环流以顺时针流动 ,近表层以下为向岸流 ,沿岸为上升流 ,近表层为离岸流 ,其在外海有明显的下降趋势 ,沿岸上升流自底层至表层逐渐由弱变强。就整个沿岸海区而论 ,冬季沿岸下降流和夏季沿岸上升流的强度都随着岸界地形坡度、风速及风向与岸线偏角的变化而变化。沿岸下降流形成的主要原因是由于冬季东北风与岸界地形的耦合效应及海区温盐分布不均匀所致 ,而沿岸上升流形成的主要原因则是由于夏季西南风与岸界地形的耦合效应及海区温盐分布不均匀所致。 相似文献
18.
On the basis of the wave energy balance equation, the response model of mean directions of locally wind-generated waves in slowly turning wind fields has been derived. The results show that in a homogeneous field, the time scale of the response is not only related to the rate of wave growth, but also to the directional energy distribution and the angle between the wind direction and the mean wave direction. Furthermore, the law of change in the mean wave direction has been derived. The numerical computations show that the response of wave directions to slowly turning wind directions can be treated as the superposition of the responses of wave directions to a series of sudden small-angle changes of wind directions and the turning rate of the mean wave direction depends on the turning rate and the total turning angles of the wind direction. The response of wave directions is in agreement with the response for a sudden change of wind directions if the change in wind directions is very fast. Based on the no 相似文献
19.
基于座底ADCP实测回波强度信号,结合短期实测悬浮体质量浓度,反演长时间序列悬浮体质量浓度,定量分析了渤海湾近一年悬浮体质量浓度变化特征及其影响因素。结果表明:受风浪影响,该区悬浮体质量浓度具有明显季节性变化特征,风浪作用强烈的季节其悬浮体浓度表现为相对高值。悬浮体净输运同样具明显季节性变化,秋冬强风浪作用下,悬浮体的净输运量明显增加;而在不同季节,月净输运方向具有不同的主输运方向。悬浮体质量浓度日变化受潮流控制明显,长周期变化则主要与风场的变化有关。潮流涨急过程与风致大浪过程均可引起沉积物再悬浮,导致悬浮体浓度明显增高。 相似文献
20.
由运动方程和涡度方程所导得的两个首次积分估计给出了海波破碎的发生条件和破碎波的波面限制。由这两个条件所构造的新的破碎波统计模式，可导出海波的破碎面积率、破碎体积率和破碎能量损耗率的解析表达式，加之一个简单的白冠物理模型又导出了一个新的白冠覆盖率的解析表达式。 相似文献