Acoustic bubble counting technique using sound speed extracted fromsound attenuation     

Bok Kyoung Choi Suk Wang Yoon 《Oceanic Engineering, IEEE Journal of》2001,26(1):125-130

Sound attenuation has been solely used to estimate bubble size distributions of bubbly water in the conventional acoustic bubble sizing methods. These conventional methods are useful for the void fraction around 10^-6 or lower. However, the change of compressibility in the bubbly water also should be considered in bubble sizing for the void fraction around 10^-5 or higher. Recently the sound speed as well as sound attenuation was considered for acoustic bubble size estimation in bubbly water. In this paper, the sound speed estimated from sound attenuation in bubbly water by an iterative method is used for a bubble counting. This new iterative inverse bubble sizing technique is numerically tested for bubble distributions of single-size Gaussian, and power-law functions. The numerical simulation results are in agreement with the given bubble distributions even for the high void fractions of 10^-4-10^-3. It suggests that the iterative inverse technique can be a very powerful tool for practical use in acoustic bubble counting in the ocean  相似文献   

Visual framework for development and use of constitutive models     

Youssef M. A. Hashash  Donald C. Wotring  John I‐Chiang Yao  Jung‐Suk Lee  Qingwei Fu 《国际地质力学数值与分析法杂志》2002,26(15):1493-1513

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Particle shape effect on thermal conductivity and shear wave velocity in sands     

Changho Lee  Hyoung Suk Suh  Boyeong Yoon  Tae Sup Yun 《Acta Geotechnica》2017,12(3):615-625

This study presents the correlations between quantified shape parameters and geotechnical properties for nine sand specimens. Four shape parameters, sphericity, convexity, elongation and slenderness, were quantified with two-dimensional microscopic images with the aid of image processing techniques. An instrumented oedometer cell is used to measure compressibility, thermal conductivity and shear wave velocity during loading, unloading and reloading stages. As the particle shape inherently determines the initial loose packing condition, initial void ratio and shape parameters are well correlated with compressibility. The applied stress in soils increases the interparticle contact area and contact quality; round particles tend to achieve higher thermal conductivity and shear wave velocity during stress-induced volume change. Multiple linear regression is implemented to capture the relative contributions of involved variables, revealing that the thermal evolution is governed by the initial packing density and particle shape. The experimental observations underscore the predominant effect that particle shape has on the geomechanical and physical properties upon stress-induced soil behavior.  相似文献   

Modified Mixed Lagrangian–Eulerian Method Based on Numerical Framework of MT3DMS on Cauchy Boundary          下载免费PDF全文

Heejun Suk 《Ground water》2016,54(4):508-520

MT3DMS, a modular three‐dimensional multispecies transport model, has long been a popular model in the groundwater field for simulating solute transport in the saturated zone. However, the method of characteristics (MOC), modified MOC (MMOC), and hybrid MOC (HMOC) included in MT3DMS did not treat Cauchy boundary conditions in a straightforward or rigorous manner, from a mathematical point of view. The MOC, MMOC, and HMOC regard the Cauchy boundary as a source condition. For the source, MOC, MMOC, and HMOC calculate the Lagrangian concentration by setting it equal to the cell concentration at an old time level. However, the above calculation is an approximate method because it does not involve backward tracking in MMOC and HMOC or allow performing forward tracking at the source cell in MOC. To circumvent this problem, a new scheme is proposed that avoids direct calculation of the Lagrangian concentration on the Cauchy boundary. The proposed method combines the numerical formulations of two different schemes, the finite element method (FEM) and the Eulerian–Lagrangian method (ELM), into one global matrix equation. This study demonstrates the limitation of all MT3DMS schemes, including MOC, MMOC, HMOC, and a third‐order total‐variation‐diminishing (TVD) scheme under Cauchy boundary conditions. By contrast, the proposed method always shows good agreement with the exact solution, regardless of the flow conditions. Finally, the successful application of the proposed method sheds light on the possible flexibility and capability of the MT3DMS to deal with the mass transport problems of all flow regimes.  相似文献   

利用远震接收函数研究黄海周边地区的地壳上地幔结构          下载免费PDF全文

Chanho Yu  Kwang-Hee Kim  Mancheol Suh  Bongchool Suk  Paul Rydelek  Suyoung Kang  Yongcheol Park  刘劲松 《地球物理学报》2010,53(6):1336-1343

利用宽频带流动台站(YSBSN)记录的远震波形数据和远震接收函数方法,反演了黄海东、西两侧地壳上地幔的S波速度结构.结果表明,莫霍面深度在30~38 km之间变化,位于中方一侧的JNN台下方地壳厚度最大,可以归因于华北板块和扬子板块的碰撞;韩方一侧的地壳厚度自北向南逐渐变厚,但仍然难以厘定朝鲜半岛南部潜在碰撞带的位置,这些问题的解决需要更大范围的流动台站观测.由于部分台站位于巨厚的沉积层和多孔的火山岩之上,与浅部构造的相关性使得接收函数表现出较大振幅的混响,从而影响了来自深部结构的转换震相.  相似文献   

Radiolarians from the Pohang Basin,Southeast Korea and Paleoceanographic Implications     

Young-Suk BAK  Jong-Deock LEE  Hyesu YUN  Jinyong OH  Seong-Joo LEE 《《地质学报》英文版》2012,86(6):1426-1433

We identified a total of 101 species and two subspecies of radiolarians belonging to 56 genera from 95 samples collected from the Hagjeon and Duho Formations in the Pohang Basin of the southeastern Korean Peninsula. On the basis of the biostratigraphic range of Cyrtocapsella cornuta and Theocorys redondoensis, the depositional period of the upper Hagjeon and lowest Duho Formations was determined to be early to late Middle Miocene. The occurrence of deep-dwelling radiolarians indicates that the paleobathymetry seems to become gradually progressing toward an upper bathyal environment in the middle part of the Hagjeon Formation. However, we prefer to accept another interpretation for the occurrence of deep-sea indicators in the Hagjeon and the lowest part of the Duho Formations, and consider the presence of a region of upwelling cold water that might have simulated a deep-water environment in relatively shallow water. This interpretation is based on the present upwelling of a cold-water mass off the southeast coast of Korea, the occurrence of upwelling microfossils from the Pohang Basin, and the effect of the closing of the Korea Strait approximately 15 Ma. We also considered that the uppermost part of the studied section represents a shallow-water environment.  相似文献   

Crystallization of loparite in alkaline fluid-magmatic systems (from experimental and mineralogical data)     

N.I. Suk  A.R. Kotel’nikov  A.A. Viryus 《Russian Geology and Geophysics》2013,54(4):436-453

We studied loparite-containing rocks (lujaurites, juvites, foyaite-juvites, etc.) sampled from a complex of differentiated rocks and, partly, from a complex of eudialytic lujaurites of the Lovozero alkaline massif. Zoned crystals of loparite (the zoning is due to variations in Ti, Nb, REE, Sr, and Th contents) were examined by microprobing. We also carried out experimental studies of loparite formation in complex silicate–salt systems including sodium carbonate, chloride, fluoride, or sulfate at 400–1200 °C and 1–2 kbar. They show that the composition of loparites depends on the physicochemical conditions of their formation (fluid composition) and that natural loparite can crystallize in a wide range of temperatures. The produced loparite crystals are zoned as a result of variations in Ti, Nb, La, Ce, Y, Ca, and Sr contents, which is probably related to the kinetic specifics of crystallization. Their zoning is similar to that of loparites of the Lovozero massif.  相似文献   

Data Assimilation Modeling of the Barotropic Tides in the Korea/Tsushima Strait     

Jeffrey?W.?BookEmail author  Pavel?Pistek  Henry?Perkins  Keith?R.?Thompson  William?J.?Teague  Gregg?A.?Jacobs  Moon-Sik?Suk  Kyung-Il?Chang  Jae-Chul?Lee  Byung?Ho?Choi 《Journal of Oceanography》2004,60(6):977-993

During 1999–2000, 13 bottom mounted acoustic Doppler current profilers (ADCPs) and 12 wave/tide gauges were deployed along two lines across the Korea/Tsushima Strait, providing long-term measurements of currents and bottom pressure. Tidally analyzed velocity and pressure data from the moorings are used in conjunction with other moored ADCPs, coastal tide gauge measurements, and altimeter measurements in a linear barotropic data assimilation model. The model fits the vertically averaged data to the linear shallow water equations in a least-squares sense by only adjusting the incoming gravity waves along the boundaries. Model predictions are made for the O₁, P₁, K₁, μ₂, N₂, M₂, S₂, and K₂ tides. An extensive analysis of the accuracy of the M₂ surface-height predictions suggests that for broad regions near the mooring lines and in the Jeju Strait the amplitude prediction errors are less than 0.5 cm. Elsewhere, the analysis suggests that errors range from 1 to 4 cm with the exception of small regions where the tides are not well determined by the dataset. The errors in the model predictions are primarily caused by bias error in the model’s physics, numerics, and/or parameterization as opposed to random errors in the observational data. In the model predictions, the highest ranges in sea level height occur for tidal constituents M₂, S₂, K₁, O₁, and N₂, with the highest magnitudes of tidal velocities occurring for M₂, K₁, S₂, and O₁. The tides exhibit a complex structure in which diurnal constituents have higher currents relative to their sea level height ranges than semi-diurnal constituents.  相似文献   

Application of a variational inverse model to determine a wintertime circulation in the East Sea of Korea     

Moon-Sik Suk 《Progress in Oceanography》1988,21(3-4)

Using a variational inverse model, a wintertime ocean circulation is obtained in the East Sea of Korea bounded by transects of 34° N, 38° N in latitude and 132° E in longitude and coastlines. The hydrographic data observed by FRDAK (Fisheries Research and Development Agency of Korea) are used for determining the vertical structure and also used as data constraints. In the current study, the model was constrained only by the geostrophic balance and bottom topography. Preliminary model results showed that the vertical distributions of temperature in February 1983 were homogeneous in the coastal region south of 35°30′ N and that the extension of cold water mass along the eastern coast of Korea was noticed in the northern part of the study area. Meandering northward flows with the scale of 150 km are also observed to be dominant in the surface layer (10–100 m).  相似文献   

Numerical Experiments of the Influences of the Transport Variation through the Korea Strait on the Japan/East Sea Upper Layer Circulation     

Sunghyea?ParkEmail author  Moon-Sik?Suk  Hui?Soo?An 《Journal of Oceanography》2005,61(1):155-165

Numerical experiments were performed in order to investigate the effects of variations of the transport through the Korea/Tsushima Strait, an inlet of the Japan/East Sea, on the upper layer circulation in the JES based on a 10-month transport observation from May 1999 to March 2000 (Perkins et al., 2000). All external forcings to the model were annual mean fields, except the transport variation through the Korea Strait. In the experiments where the periodic variation of the transport repeated continuously sinusoidally by several periods, strong variability of sea surface height (SSH) was detected in the region extending from the Korea Strait to the Japanese coast due to the geostrophy of the buoyancy forcing at the Korea Strait. The region along the Korean coast is more sensitive to the long-term variations than the short-term (≤60-day period) ones. In two experiments forced by realistic and monthly mean transport, the difference of rms of sea surface height was largest at the Japanese coast and relatively large at the East Korean Warm Current separation region (128∼130°E, 39∼41°N) and to the east of Yamato Rise. The distribution of difference of eddy kinetic energy at 100 m depth between the two experiments was similar to that of the rms of SSH. In the distributions of mean SSH and mean kinetic energy at 100 m depth the realistic transport invokes eddy variability to interact with mean current resulting in the changes of the mean SSH and the mean kinetic energy at the East Korean Warm Current separation region, but it does not produce conspicuous changes in the mean fields of entire JES compared with the mean fields forced by the seasonal transport.  相似文献