Modeling of wave processes in closed water areas of shallow water areas

2021 ◽  
pp. 30-35
Author(s):  
Eugene Istomin ◽  
Valerii Mikheev ◽  
Yaroslav Petrov ◽  
Irma Martyn
Keyword(s):  
Water Area ◽  
Navier Stokes ◽  
Coastal Protection ◽  
Wave Processes ◽  
Color Palette ◽  
Continuity Equations ◽  
Port Area ◽  
Wave Heights ◽  
Closed Water ◽  
Hydrostatic Model

The article presents the developed non-stationary two-dimensional hydrostatic model of wave propagation in the water area of the port of the Bay of Five Hunters, protected by a coastal protection structure in the form of a jetty. The tasks of the work included the development of a model based on the Navier-Stokes and continuity equations and a long-range assessment of the possible impact of the wave situation on marine objects in the port area. At present, the provision of hydrometeorological predictive information is one of the most important factors in the effective operation of port waters. The results are presented graphically using a geographic information system, where different wave heights and maximum wave amplitudes are displayed using a color palette. The consistency of the obtained results is shown, and refraction, diffraction, and interference are noted for the incoming wavefront.

HYDRODYNAMIC WAVE PROCESSES NUMERICAL MODELING IN THE COASTAL RECREATIONAL ZONE OF THE TSIMLYANSK RESERVOIR

2021 ◽  
pp. 36-43
Author(s):  
A.I. Sukhinov ◽  
V.V. Sidoryakina ◽  
E.A. Protsenko
Keyword(s):  
Numerical Algorithms ◽  
Correction Method ◽  
Water Area ◽  
Navier Stokes ◽  
Northwestern Part ◽  
Water Medium ◽  
Reservoir Water ◽  
Wave Regime ◽  
Continuity Equations ◽  
Hydrodynamic Wave

This paper presents the results of wave regime hydrophysical characteristics calculations in the area of the accumulative shore of the Tsimlyansky reservoir northwestern part. Wave hydrodynamics model based on 3D mathematical model that includes three Navier-Stokes motion equations, the continuity equations for an incompressible fluid was used. The discretization of the hydrodynamic equations was performed using the pressure correction method. Numerical algorithms and the software package implementing them are used to determine the pressure field, the water medium velocity vector field and to plot the pressure a given section of the reservoir water area. The results of the study can be used in the study of hydrophysical processes, assessment of the hydrodynamic impact on the formation of the coast-line and the bottom relief of large plaintype reservoirs in the Southern Russia.

scholarly journals Effect of an oscillating time-dependent pressure gradient on Dean flow: transient solution

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Basant K. Jha ◽  
Dauda Gambo
Keyword(s):  
Pressure Gradient ◽  
Initial Conditions ◽  
Fluid Velocity ◽  
Outer Cylinder ◽  
Time Dependent ◽  
Navier Stokes ◽  
Dean Flow ◽  
Continuity Equations ◽  
Riemann Sum ◽  
Flow Formation

Abstract Background Navier-Stokes and continuity equations are utilized to simulate fully developed laminar Dean flow with an oscillating time-dependent pressure gradient. These equations are solved analytically with the appropriate boundary and initial conditions in terms of Laplace domain and inverted to time domain using a numerical inversion technique known as Riemann-Sum Approximation (RSA). The flow is assumed to be triggered by the applied circumferential pressure gradient (azimuthal pressure gradient) and the oscillating time-dependent pressure gradient. The influence of the various flow parameters on the flow formation are depicted graphically. Comparisons with previously established result has been made as a limit case when the frequency of the oscillation is taken as 0 (ω = 0). Results It was revealed that maintaining the frequency of oscillation, the velocity and skin frictions can be made increasing functions of time. An increasing frequency of the oscillating time-dependent pressure gradient and relatively a small amount of time is desirable for a decreasing velocity and skin frictions. The fluid vorticity decreases with further distance towards the outer cylinder as time passes. Conclusion Findings confirm that increasing the frequency of oscillation weakens the fluid velocity and the drag on both walls of the cylinders.

scholarly journals Obtaining Expressions for Time-Dependent Functions That Describe the Unsteady Properties of Swirling Jets of Viscous Fluid

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1860
Author(s):  
Eugene Talygin ◽  
Alexander Gorodkov
Keyword(s):  
Blood Flow ◽  
Viscous Fluid ◽  
Swirling Flow ◽  
Fluid Flows ◽  
Theoretical Method ◽  
Flow Channel ◽  
Navier Stokes ◽  
Swirling Jets ◽  
Continuity Equations ◽  
Dynamic Velocity

Previously, it has been shown that the dynamic geometric configuration of the flow channel of the left heart and aorta corresponds to the direction of the streamlines of swirling flow, which can be described using the exact solution of the Navier–Stokes and continuity equations for the class of centripetal swirling viscous fluid flows. In this paper, analytical expressions were obtained. They describe the functions C0t and Г0t, included in the solutions, for the velocity components of such a flow. These expressions make it possible to relate the values of these functions to dynamic changes in the geometry of the flow channel in which the swirling flow evolves. The obtained expressions allow the reconstruction of the dynamic velocity field of an unsteady potential swirling flow in a flow channel of arbitrary geometry. The proposed approach can be used as a theoretical method for correct numerical modeling of the blood flow in the heart chambers and large arteries, as well as for developing a mathematical model of blood circulation, considering the swirling structure of the blood flow.

scholarly journals Computational Analysis to Factor Wind into the Design of an Architectural Environment

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Hassam Nasarullah Chaudhry ◽  
John Kaiser Calautit ◽  
Ben Richard Hughes
Keyword(s):  
Fluid Dynamics ◽  
Power Generation ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Numerical Data ◽  
Navier Stokes ◽  
Windward Side ◽  
Average Value ◽  
Continuity Equations ◽  
Prevailing Wind Direction

The effect of wind distribution on the architectural domain of the Bahrain Trade Centre was numerically analysed using computational fluid dynamics (CFD). Using the numerical data, the power generation potential of the building-integrated wind turbines was determined in response to the prevailing wind direction. The three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations along with the momentum and continuity equations were solved for obtaining the velocity and pressure field. Simulating a reference wind speed of 6 m/s, the findings from the study quantified an estimate power generation of 6.4 kW indicating a capacity factor of 2.9% for the benchmark model. At the windward side of the building, it was observed that the layers of turbulence intensified in inverse proportion to the height of the building with an average value of 0.45 J/kg. The air velocity was found to gradually increase in direct proportion to the elevation with the turbine located at higher altitude receiving maximum exposure to incoming wind. This work highlighted the potential of using advanced computational fluid dynamics in order to factor wind into the design of any architectural environment.

scholarly journals LABORATORY STUDY ON PERVIOUS CORE BREAKWATERS

1976 ◽  
Vol 1 (15) ◽  
pp. 151
Author(s):  
Hideo Kondo ◽  
Satoshi Toma ◽  
Kenji Yano
Keyword(s):  
Second Harmonic ◽  
Core Layer ◽  
Water Area ◽  
Transmitted Wave ◽  
Circular Cylinders ◽  
Perforated Plates ◽  
Wave Heights ◽  
Wave Distribution ◽  
Core Thickness ◽  
Made In

Effects of permeable core layer installed in trapezoidal and rectangular breakwaters have been studied experimentally and analytically. As the materials for armour and core use of the lattice composed of circular cylinders was made in addition to rocks. Perforated plates were also applied as a kind of very thin core. Expermental results show that the reflected wave heights from breakwater could be reduced considerably by locating the core layer shoreward within it while core thickness controls the transmitted wave heights in the protected water area. Harmonic analysis about the water surface in lattice armour reveals that the second harmonic waves take a pattern of standing wave distribution having a node at the seaward face of breakwater. Thin perforated plates work success-- fully for reducing the transmitted wave heights when they are installed at the rear face of breakwater. An analytical approach to predict the transmission and the reflection coefficients is applied for the present experimental data and shown to be useful.

scholarly journals THE SUITABILITY ECOTOURISM BEACH BASED GEOSPATIAL IN PADANG CITY – INDONESIA : CASE STUDY OF CATEGORY RECREATION BEACH AND MANGROVE

Jurnal Segara ◽  
2018 ◽  
Vol 14 (2) ◽  
Author(s):  
Aprizon Putra
Keyword(s):  
Water Area ◽  
Coastal Protection ◽  
Small Islands ◽  
Research Results ◽  
A Value ◽  
The Matrix

Padang city has a coastline 80.24 km with a water area 72,000 ha, and 19 small islands. Overall, coastal in Padang City consists of beach sloping 41.52 km, cliff 22.08 km, muddy 8.19 km, and type of artificial beach in form of building coastal protection. The research aims at identifying suitability for ecotourism beach (category of recreation beach and mangrove). The methodology used ie with the matrix of suitability ecotourism beach using geospatial approach. Research results for suitability category recreation beach in 24 locations in beach Padang City 18 locations are in the category of very suitable with a value 82.28 % and only beach in Bung Hatta University are in category conditional with a value 27 %. Suitability category ecotourism mangrove in 19 locations in beach Padang City 6 location is in a category is in accordance with a value 92.11 % and 4 location is in a category conditional/not suitable to value 50.88 %.

scholarly journals Airflow inside the nasal cavity: visualization using computational fluid dynamics

2010 ◽  
Vol 4 (4) ◽  
pp. 657-661 ◽  
Author(s):  
Mohammed Zubair ◽  
Vizy Nazira Riazuddin ◽  
Mohammed Zulkifly Abdullah ◽  
Rushdan Ismail ◽  
Ibrahim Lutfi Shuaib ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nasal Cavity ◽  
Three Dimensional ◽  
Clinical Importance ◽  
Navier Stokes ◽  
Tomographic Images ◽  
Computed Tomographic ◽  
Continuity Equations ◽  
Cfd Method

Abstract Background: It is of clinical importance to examine the nasal cavity pre-operatively on surgical treatments. However, there is no simple and easy way to measure airflow in the nasal cavity. Objectives: Visualize the flow features inside the nasal cavity using computational fluid dynamics (CFD) method, and study the effect of different breathing rates on nasal function. Method: A three-dimensional nasal cavity model was reconstructed based on computed tomographic images of a healthy Malaysian adult nose. Navier-Stokes and continuity equations for steady airflow were solved numerically to examine the inspiratory nasal flow. Results: The flow resistance obtained varied from 0.026 to 0.124 Pa.s/mL at flow-rate from 7.5 L/min to 40 L/min. Flow rates by breathing had significant influence on airflow velocity and wall shear-stress in the vestibule and nasal valve region. Conclusion: Airflow simulations based on CFD is most useful for better understanding of flow phenomenon inside the nasal cavity.

HYDRODYNAMIC CALCULATION OF CONTACTLESS SEALS WITH PLANE SLOTS IN DRIVES OF ELECTRIC POWER SYSTEMS

2021 ◽  
Vol 11 (2) ◽  
pp. 171-177
Author(s):  
Evgeny A. KRESTIN ◽  
Grigoriy V. SEREBRYAKOV
Keyword(s):  
Pressure Drop ◽  
Power Systems ◽  
Electric Power ◽  
Constant Pressure ◽  
Saturated Vapor ◽  
Electric Power Systems ◽  
Navier Stokes ◽  
Friction Forces ◽  
Continuity Equations ◽  
Special Cases

Non-contact seals with fl at slott ed gaps of drives of electric power systems used in switchgears of hydraulic units, as well as in pumps and hydraulic motors have been investigated. Calculation of seals based on average clearance results in an underestimation or overestimation of the leakage rate compared to the operational values. The regularity of the distribution of pressure and fl ow rate in the gap of a fl at conical slot is determined, and formulas for the fl ow rate (leakage) and friction forces acting on the walls of the conical slot are found. To solve the problem, the approximate Navier-Stokes and fl ow continuity equations are used. Several special cases of the fl ow of the working fl uid in diff erent gaps are considered: a plane-parallel gap with an oscillating wall and at a constant pressure gradient and a conical gap at diff erent ratios of the pressure drop and the frictional action of the moving channel wall. When the wall oscillates in a conical gap and constant pressure, the presence of an extremum is characteristic. In this case, an excess pressure appeared in the slott ed gap, creating a supporting force, and the pressure value became high enough. When the lower wall of the conical slot moves in the direction of the increasing gap, the pressure inside the slott ed channel, under certain conditions, can reach a complete vacuum, the value of which is limited by the bulk strength of the liquid and the pressure of saturated vapor at a given temperature. When the pressure drop and oscillations of the wall of the conical gap are additive, then at a suffi ciently high velocity of the wall movement, the pressure inside the slot can even increase and exceed the value of the supplied pressure.

An investigation on the instability of a flexible liquid-filled rotor

2019 ◽  
Vol 234 (2) ◽  
pp. 165-172
Author(s):  
Guangding Wang ◽  
Huiqun Yuan ◽  
Hongyun Sun
Keyword(s):  
Stokes Equations ◽  
Fluid Motion ◽  
Coupling Model ◽  
Frequency Equation ◽  
Rotor System ◽  
System Stability ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Continuity Equations ◽  
The Stability

In this paper, the stability of a flexible rotor partially filled with liquid is investigated. On the basis of the Navier-Stokes equations for the incompressible flow, a two-dimensional analytical model is developed for fluid motion. Applying the perturbation method, the linearized Navier-Stokes and continuity equations of fluid particles are obtained. Using the boundary conditions of fluid motion, the fluid forces exerted on the rotor are calculated. According to the established fluid-structure coupling model of the rotor system, the whirling frequency equation, which is applied to determine the stability of the system, is derived. The analysis results of the system stability are compared with the theoretical ones reported in the previous study. Good agreement is shown between the results of the present analysis and the literature results. The influences of the main parameters on the dynamic stability of the rotor system are discussed.

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