V. Prabu Kumar
Bio: V. Prabu Kumar is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Curtain wall & Caisson. The author has an hindex of 1, co-authored 2 publications receiving 1 citations.
TL;DR: In this paper, the wave-structure interaction of a caisson type offshore intake well with the regular waves was investigated with and without curtain w.r.t. a 1:20 scale model.
Abstract: The present study focus on the wave-structure interaction of a caisson type offshore intake well with the regular waves. A 1:20 scale model is experimentally investigated with and without curtain w...
••01 Jan 2021
TL;DR: In this paper, the internal hydrodynamics of an offshore intake well with a porous curtain wall were investigated with regular waves in the shallow wave basin and wave run-up, rundown, free surface water oscillation inside the well and the pressure acting on the curtain wall was measured.
Abstract: The purpose of offshore seawater intake is to provide a continuous supply of seawater with proper quantity and quality. The large volume and specified water quality requirements, offshore intake wells are preferred. The adequate and economical supply of seawater from the offshore intake well depends on the performance of the pumping system. In a typical intake well, the pumping equipment is placed below the water surface based on the free surface water oscillation inside the well. The loads exerted by the incoming waves and the free surface water oscillation will affect the pumping performance. This phenomenon should be reduced for smooth and efficient pumping operation. To achieve this, some auxiliary equipment like curtain wall is introduced into the intake well. This type of internal structure can regulate the flow and dissipate the incident wave energy up to some extent. Moreover, they can obstruct the formation of vortices and eddying. The present study focuses on the internal hydrodynamics of an offshore intake well with a porous curtain wall. A 1:20 scale model is tested with regular waves in the shallow wave basin and wave run-up, rundown, free surface water oscillation inside the well and the pressure acting on the curtain wall is measured. Then, the influence of the porosity on the free surface water oscillation is investigated by changing the porosity.
TL;DR: In this paper , the authors explore scenarios for avoiding or resolving hydraulic problems that have arisen as a result of hydraulic model studies and show that the designer should make every effort to avoid small entrance and filtration areas from the basin to the intake forebay bottom, which could result in jet outlet and/or supercritical flow.
Abstract: In recent years, tapping the sea for potable water has gained prominence as a potential source of water. Since seawater intake systems are often used in the infrastructure industry, ensuring proper efficiency in different operating conditions is very important. In this paper, CFD modeling is used to show general hydraulic design (flow patterns, stream flow, vortex severities, and pre-swirl) principles and performance acceptability criteria for pump intakes in different conditions. The authors explore scenarios for avoiding or resolving hydraulic problems that have arisen as a result of hydraulic model studies. The results show that the designer should make every effort to avoid small entrance and filtration areas from the basin to the intake forebay bottom, which could result in jet outlet and/or supercritical flow; too small logs at the basin outflow, which could result in high velocity flow jets; and sudden area contractions at the forebay to pump bay junction. There should be enough submergence at the pumps to reduce harmful vortex severities and pre-swirl. Curtain walls, baffles, fillets, and splitters, as well as flow redistributors, can all aid in improving approach flow patterns. Reduced flow separations and eddies will be greatly assisted by rounding corners and providing guide walls. Using a numerical model to figure out what is wrong and how to fix it will help the facility’s costs and maintenance decrease in the long run.
01 Dec 1976
TL;DR: In this paper, the forces and overturning moments exerted by waves on large vertical circular cylinders have been measured in the laboratory and a design method is presented which allows the wave loads on large circular cylinders to be estimated by means of a simple desk calculation.
Abstract: : The forces and overturning moments exerted by waves on large vertical circular cylinders have been measured in the laboratory. Two rigid cylinders, 12 in. and 26.5 in. in diameter, extending from the bottom of a wave flume through the water surface, were tested in varying depths of water, for a range of wave periods and wave heights up to the point of breaking. A digital computer was used for the acquisition, processing, plotting and storage of the experimental data. In addition to the experimental work, a design method is presented which allows the wave loads on large circular cylinders to be estimated by means of a simple desk calculation. The experimental data shows that this simple method of calculation, based on the linear diffraction theory of MacCamy and Fuchs, is accurate over a wide range of wave conditions and cylinder sizes. (Author)
21 Feb 2022
TL;DR: In this article , the wave-structure interaction of an offshore intake well with a curtain wall is computationally investigated with regular waves using ANSYS-FLUENT, Computational Fluid Dynamics (CFD) tool.
Abstract: The wave-structure interaction of an offshore intake well with a curtain wall is computationally investigated with regular waves. The simulation is done using ANSYS-FLUENT, Computational Fluid Dynamics (CFD) tool. The computational domain is governed by continuity and the Reynolds Averaged Navier-Stokes (RANS) equations and modeled in a Cartesian grid system. The combination of structured and unstructured mesh is used to discretize the simulation domain. The numerical model is developed based on the pressure-based transient solver, and the Volume of Fluid (VOF) technique is selected to trace the free surface elevation. The simulations are performed using the 1:20 scale model by varying wave period (T) and wave steepness (H/L). The run-up on the seaward face and pressure on both sides of the curtain wall are measured. The numerical run-up shows good agreement with the experiments for the d/L range of 0.15 to 0.36. The pressure on both sides decreases with increased d/L values and follows the same trend as experiments.
TL;DR: In this paper , a new seawater intake caisson with an oscillating water column wave energy conversion device is proposed to improve water quality and electricity compensation, which can also realize a certain compensation for the electricity consumption required for pumping water.
Abstract: Seawater intake caissons are a kind of structure widely used in seawater extraction. Many existing seawater intake caissons have problems with poor water quality and large power consumption. In this paper, a new type of seawater intake caisson with an oscillating water column wave-energy conversion device is proposed to improve water quality and electricity compensation. A wave-energy conversion device at the front end of the structure can reduce the disturbance of wave energy to the rear water intake area, which is conducive to sediment deposition. In the meantime, it can also realize a certain compensation for the electricity consumption required for pumping water. Based on the two-phase flow solver (OpenFOAM-4.x), through a comparison and analysis of streamlining and flow velocity in the rear water intake area, it was found that the water purification effects of the integrated structure proved more effective than those of the traditional structure, and the overall average velocity of the flow field reduced by 10%–40%. The optimal energy conversion efficiency of the integrated structure was obtained by optimizing different parameters such as the ratio of the chamber width to the wavelength, the orifice size, the draft of the front wall, and the draft of the intermediate baffle.Practical ApplicationsSeawater intake systems are widely used for seawater extraction. Many seawater intake structures suffer from poor water quality and large power consumption due to the large volume of water extraction. A new structure is proposed, which sets an oscillating water column wave energy–converting device on the front side of the traditional seawater intake caisson to capture wave energy. The working process is divided into three stages: firstly, waves enter the device. Wave surface oscillation causes air exhalation and suction to drive the blade rotation, and the generator rotor also rotates to generate electricity; secondly, the flow enters the water intake area and wave energy is significantly weakened by the reflection from the front and back walls of the chamber; finally, the relatively pure seawater is lifted through the pump to the water intake pipeline. The performance of the proposed device is evaluated by comparing the flow field changes of the proposed device and the traditional one and analyzing the energy conversion efficiency of the proposed device. The new structure is verified to have the dual effects of water purification and wave-energy conversion.
TL;DR: In this article , the hydrodynamic properties and proximity effects of dual offshore intake wells installed in the vicinity of a regular wave environment were investigated, where the intake wells were placed at the separation distance (S) equal to the diameter of the intake well, and the interaction was studied by changing the orientation (θ).
Abstract: This paper investigates the hydrodynamic properties and proximity effects of dual offshore intake wells installed in the vicinity. The physical model study is carried out with 1:20 scale models in a regular wave environment. The intake wells are placed at the separation distance (S) equal to the diameter of the intake well (D), and the interaction is studied by changing the orientation (θ). The wave run-up and rundown around the wells, free surface water oscillation at the inlet and pumping chambers, and diffraction wave heights are measured for each configuration. The influence of θ on these parameters is analyzed to get insight into the non-linear responses captured during the wave structure interaction.