scholarly journals Rijeka Bay 3D VOF Costal Flow Model

2020 ◽  
Vol 3 (3) ◽  
pp. 125-132
Author(s):  
Lado Kranjčević ◽  
Luka Grbčić ◽  
Matija Mrazović ◽  
Siniša Družeta

3D multiphase flow was analyzed in the area of Rijeka bay in the Adriatic Sea. The necessary morphology data in the range of interest of the coastal bottom area were collected and the spatial surface was created. The functionality of the 3D model was studied in the large area of the realistic stochastic structure of the bottom and the shore. The probability of meteorological conditions and wind impact in the model has been shown. The obtained results give a detailed view of the velocity fields in the horizontal plane of different depths. Numerical simulation was performed in open source program OpenFOAM with Volume of Fluid (VOF) method using the Eulerian approach. For solving this problem interFOAM solver for two incompressible, isothermal, immiscible fluids was used. The resulting simulations showed dominant flow from the western coast of the Krk island to the eastern coast of the Istrian peninsula. Seawater enters the bay through the Srednja Vrata and Tihi Kanal and exits the bay through the Vela Vrata. This research has shown that using a VOF method can be successfully implemented for describing fluid motion in large areas such as bays and oceans.

2020 ◽  
Vol 324 (2) ◽  
pp. 262-272
Author(s):  
I.V. Doronin ◽  
T.N. Dujsebayeva ◽  
K.M. Akhmedenov ◽  
A.G. Bakiev ◽  
K.N. Plakhov

The article specifies the type locality of the Steppe Ribbon Racer. The holotype Coluber (Taphrometopon) lineolatus Brandt, 1838 is stored in the reptile collection of the Zoological Institute of the Russian Academy of Sciences (ZISP No 2042). Literature sources provide different information about the type locality. A mistake has been made in the title of the work with the original species description: the western coast of the sea was indicated instead of the eastern one. The place of capture was indicated as “M. Caspium” (Caspian Sea) on the label and in the reptile inventory book of the Zoological Museum of the Academy of Sciences. The specimen was sent to the museum by G.S. Karelin. The “1842” indicated on the labels and in the inventory book cannot be the year of capture of the type specimen, just as the “1837” indicated by A.M. Nikolsky. In 1837, Karelin was in Saint Petersburg and in 1842 in Siberia. Most likely, 1837 is the year when the collection arrived at the Museum, and 1842 is the year when the information about the specimen was recorded in the inventory book (catalog) of the Zoological Museum of the Academy of Sciences. In our opinion, the holotype was caught in 1932. From Karelin’s travel notes of the expedition to the Caspian Sea in 1832, follows that the snake was recorded in two regions adjacent to the eastern coast of the Caspian Sea – Ungoza Mountain (“Mangyshlak Mountains”) and site of the Western Chink of Ustyurt between Zhamanairakty and Kyzyltas Mountains (inclusive) on the northeast coast of Kaydak Sor (“Misty Mountains”). In our article, Karelin’s route to the northeastern coast of the Caspian Sea in 1832 and photographs of these localities are given. The type locality of Psammophis lineolatus (Brandt, 1838) should be restricted to the Mangystau Region of the Kazakhstan: Ungoza Mountain south of Sarytash Gulf, Mangystau (Mangyshlak) Penninsula (44°26´ N, 51°12´ E).


1995 ◽  
Vol 46 (3) ◽  
pp. 583 ◽  
Author(s):  
RJQ Tarr

Growth rates of a number of Haliotis midae populations around the South African coast were studied by means of tagging. These populations ranged from the cool waters of the western coast to the more temperate environment of the eastern Cape. Standard von Bertalanffy growth curves were fitted and growth parameters derived. These ranged from 0.19 to 0.25 for K, the average rate at which L∞ is approached, and from 156 to 173 for L∞, the average theoretical maximum length. These indicate far higher growth rates than were previously published for this commercially fished species, and the reasons for this difference are discussed. The expectation that growth rates would be fastest in the warmer eastern Cape waters was not realized, there being no significant difference in growth between the Bird Island population on the eastern coast and the Robben Island population on the western coast. These new growth parameters indicate that H. midae in the commercial fishery grounds is attaining sexual maturity some four years earlier, and the minimum legal size some five years earlier, than previously considered. This has considerable significance for modelling studies presently underway. Movement of a small population of adult H. midae was studied over a three-year period, after which 47% of the original abalone were still present on the study site. Of these, 81.5% still occupied exactly the same position on the rocks. This indicates that H. midae that have located an optimum habitat, and that are not disturbed, tend not to move.


2018 ◽  
Author(s):  
Paul C. Rivera

The formation of tsunami swirls near the coast is an obvious oceanographic phenomenon during the occurrence of giant submarine earthquakes and mega-tsunamis. Several tsunami vortices were generated during the Asian tsunami of 2004 and the great Japan tsunami of March 2011 which lasted for several hours.New models of tsunami generation and propagation are hereby proposed and were used to investigate the tsunami inception, propagation and associated formation of swirls in the eastern coast of Japan. The proposed generation model assumes that the tsunami was driven by current oscillations at the seabed induced by the submarine earthquake. The major aim of this study is to develop a tsunami model to simulate the occurrence of tsunami swirls. Specifically, this study attempts to simulate and understand the formation of the mysterious tsunami swirls in the northeast coast of Japan. In addition, this study determines the vulnerability of the Philippines to destructive tsunami waves that originate near Japan. A coarse-resolution model was therefore developed in a relatively large area encompassing Japan Sea and the eastern Philippine Sea. On the other hand, a fine-resolution model was implemented in a small area off Sendai coast near the epicenter. The model result was compared with the tsunami record obtained from the National Data Buoy Center with relatively good agreement as far as the height and period of the tsunami are concerned. Furthermore, the fine-resolution model was able to simulate the occurrence of tsunami vortices off Sendai coast with various sizes that lasted for several hours.


2018 ◽  
Vol 43 ◽  
pp. 111-116
Author(s):  
Mustapha Hassoun ◽  
Hanaa Moussa ◽  
Ghizlane Salhi ◽  
Hanaa Zbakh ◽  
Hassane Riadi ◽  
...  

AbstractWe report new records and corological data for three Moroccan marine macroalgae that complete their distribution information. Radicilingua thysanorhizans is new record for Morocco; Champia compressa is recorded for the first time from the eastern coast of the Atlantic Ocean. Diplothamnion jolyi is widely distributed in the western coast of the Atlantic coast and Pacific Islands, and recently reported from the Mediterranean Sea; this new record from Moroccan Atlantic coast extends their distribution range.Key words: Algae, Atlantic Ocean, Champia compressa, Diplothamnion jolyi, Radicilingua thysanorhizans.ResumenSe aportan nuevos registros y datos corológicos para tres macroalgas marinas de Marruecos, que completan la información sobre su distribución. Radicilingua thysanorhizans es cita nueva para Marruecos. Champia compressa se registra por la primera vez en la costa oriental del Océano Atlántico. Diplothamnion jolyi se distribuye ampliamente en la costa occidental de la costa atlántica y las islas del Pacífico y ha sido recientemente citada en el mar Mediterráneo; esta nueva cita para costa Atlántica Marroquí amplia su rango de distribución.Palabras clave: Algae, Océano Atlántico, Champia compressa, Diplothamnion jolyi, Radicilingua thysanorhizans.


2003 ◽  
Vol 3 (3) ◽  
pp. 2547-2573 ◽  
Author(s):  
J. Smolik ◽  
V. Ždimal ◽  
J. Schwarz ◽  
M. Lazaridis ◽  
V. Havránek ◽  
...  

Abstract. A Berner low pressure impactor was used to collect size-segregated aerosol samples at Finokalia, located on the north-eastern coast of Crete, Greece during July 2000 and January 2001. Several samples were also collected during the summer campaign aboard the research vessel "AEGAIEO" in the Aegean Sea. Gravimetric analysis and inversion techniques yielded daily PM1 and PM10 mass concentrations. Further, the samples were analysed by PIXE giving elemental size distributions of Al, Si, K, Ca, Ti, Mn, Fe, Sr, S, Cl, Ni, V, Cu, Cr, Zn, and Pb. The crustal elements and sea-salt had a unimodal supermicron size distribution. Sulphur was found predominantly in submicron fractions. K, V, and Ni exhibited bimodal distribution with a submicron mode produced by forest fires and oil combustion. The anthropogenic elements had broad and not well-defined distributions. The time series for PM1 and PM10 mass and elemental concentrations showed both daily and seasonal variation. Higher mass concentrations were observed during two incursions of Saharan dust. Higher concentrations of S, Cu, Zn, and Pb were encountered in samples collected in air masses arriving from northern Greece or the western coast of Turkey. Higher concentrations of chlorine were found in samples with air masses either originating above the Atlantic Ocean and arriving at Finokalia via western Europe or recirculating over the western coast of the Black Sea.


2014 ◽  
Vol 13 (1) ◽  
pp. 65
Author(s):  
A. A. Horta ◽  
L. O. S. Ferreira ◽  
E. L. Martinez ◽  
R. Maciel Filho

Multiphase fluid motion in microchannnels involves complicated fluid dynamics and is fundamentally important to diverse practical engineering applications. Among several applications, the alcohol-oil mixture is particularly important due to its application for biodiesel production. In this work, the mixture of immiscible fluids alcohol-oil in a square T-shaped microchannel was investigated using the Dissipative Particle Dynamics (DPD) method available in the HOOMD simulator, which runs on a single graphic processing unit (GPU). The immiscible fluids were achieved by increasing the repulsive force between species. The fluid properties and hydrodynamic behavior were discussed in function of model parameters. The simulation results agree with data published in the literature showing that the DPD is appropriate for simulation of mass transport on complex geometries in microscale on a single GPU.


Author(s):  
M. A. Al-Rawi ◽  
A. M. Al-Jumaily ◽  
A. Lowe

Non-invasive diagnosis of cardiovascular diseases is a valuable tool to reduce patient’s risk and discomfort. The main aim of this work is to investigate the possibilities of using computational fluid dynamics as a tool to investigate the biomechanical characteristics of the aorta under different medical conditions. These conditions include an aorta with healthy conditions, atherosclerosis and aneurysm. A three dimensional pulsatile flow model for an elastic aorta is developed and constructed in ANSYS® CFX 12. Abnormalities are simulated as diameter changes at the root of the ascending aorta. The computational model shows the reflection of these diseases on the blood flow and the artery wall at other locations downstream along the aorta. This 3D model has several advantages over previously published 1D and 2D models by giving more realistic results as compared with clinical trials.


2015 ◽  
Author(s):  
A. Demerdzhiev ◽  
St. Lishev ◽  
Kh. Tarnev ◽  
A. Shivarova

1980 ◽  
Vol 58 (11) ◽  
pp. 2116-2119 ◽  
Author(s):  
R. W. Blake

A simple fluid flow model, based on momentum considerations, is employed to calculate the hydromechnanical efficiency of the undulatory dorsal fin propeller of the electric fish (Gymnarchus niloticus) and the seahorse (Hippocampus hudsonius). The undulatory fins of G. niloticus and H. hudsonius are representative of two extreme kinematic styles. The dorsal fin of G. niloticus is characterized by waveforms which are propagated at low frequency and a leading edge which "sweeps out" a large area. In contrast, the leading edge of the dorsal fin of H. hudsonius sweeps out a comparatively small area and waveforms pass down the fin at a high frequency. It is shown that the propulsive efficiency of the dorsal fin of G. niloticus can be up to twice that of H. hudsonius at similar swimming speeds. Possible explanations for the evolution of the two kinematic modes are discussed in relation to the mode of life of the animals.


Author(s):  
Taimei Miyagawa ◽  
Yohsuke Imai ◽  
Ikuma Kobayashi ◽  
Takuji Ishikawa ◽  
Takami Yamaguchi

Functions of the stomach are storage, mixing and emptying of gastric contents. Among these functions, we focus on the gastric mixing. The stomach shows an antral contraction wave (ACW) that propagates from the proximal antrum to the pylorus. Previous studies using high-resolution concurrent manometry and magnetic resonance imaging (MRI) have suggested that the ACW plays an important role in the gastric mixing. However it is difficult to observe in vivo intragastric fluid motion in detail.


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