scholarly journals Liquid Sloshing in a Horizontal Circular Container with Eccentric Tube under External Excitation

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Mohammad Nezami ◽  
Mohammad Mehdi Mohammadi ◽  
Atta Oveisi
Keyword(s):  
Numerical Solutions ◽  
Lateral Acceleration ◽  
Linear Potential ◽  
Linear Sets ◽  
Inviscid Incompressible Fluid ◽  
Laplace Transform Technique ◽  
Tube Type ◽  
Eccentric Tube ◽  
Linear Potential Theory ◽  
Turning Maneuver

Appropriate conformal mapping transformation in combination with the linear potential theory is employed to develop mathematical model for two-dimensional sloshing in horizontal circular cylindrical containers with overall eccentric hole. The tube-type tank is filled with inviscid incompressible fluid up to its half depth and subjected to lateral accelerations. A ramp-step excitation encountered in a road turning maneuver as well as real seismic event is used to simulate the lateral acceleration excitation. The resulting linear sets of ordinary differential equations are truncated and then solved numerically by employing Laplace transform technique followed by Durbin’s numerical inversion pattern. The effects of excitation input time, eccentricity, and radii ratio on the hydrodynamic responses and suppression of the induced destabilizing lateral forces are examined. Limiting cases are considered and good agreements with available analytic and numerical solutions as well as the simulations performed by using a commercial FEM software package are obtained.

Simulation of Multiliquid-Layer Sloshing With Vessel Motion by Using Moving Particle Semi-Implicit Method

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Kyung Sung Kim ◽  
Moo-Hyun Kim ◽  
Jong-Chun Park
Keyword(s):  
Gas Production ◽  
Particle Simulation ◽  
Small Scale ◽  
Linear Potential ◽  
Operational Effectiveness ◽  
Mps Method ◽  
Moving Particle ◽  
Vessel Motion ◽  
Linear Potential Theory ◽  
Oil Gas

For oil/gas production/processing platforms, multiple liquid layers can exist and their respective sloshing motions can also affect operational effectiveness or platform performance. To numerically simulate those problems, a new multiliquid moving particle simulation (MPS) method is developed. In particular, to better simulate the relevant physics, robust self-buoyancy model, interface searching model, and surface-tension model are developed. The developed multiliquid MPS method is validated by comparisons against experiment in which three-liquid-sloshing experiment and the corresponding linear potential theory are given. The validated multiliquid MPS program is subsequently coupled with a vessel-motion program in time domain to investigate their dynamic-coupling effects. In case of multiple liquid layers, there exists a variety of sloshing natural frequencies for respective interfaces, so the relevant physics can be much more complicated compared with the single-liquid-tank case. The simulation program can also reproduce the detailed small-scale interface phenomenon called Kelvin–Helmholtz instability. The numerical simulations also show that properly designed liquid cargo tank can also function as a beneficial antirolling device.

A comparative study of heat transfer analysis of fractional Maxwell fluid by using Caputo and Caputo–Fabrizio derivatives

2020 ◽  
Vol 98 (1) ◽  
pp. 89-101 ◽  
Author(s):  
Nauman Raza ◽  
Muhammad Asad Ullah
Keyword(s):  
Exact Solutions ◽  
Fractional Derivatives ◽  
Numerical Solutions ◽  
Maxwell Fluid ◽  
Heat Transfer Analysis ◽  
Flow Parameters ◽  
Fluid Parameter ◽  
Laplace Transform Technique ◽  
The Laplace Transform ◽  
Temperature And Velocity Fields

A comparative analysis is carried out to study the unsteady flow of a Maxwell fluid in the presence of Newtonian heating near a vertical flat plate. The fractional derivatives presented by Caputo and Caputo–Fabrizio are applied to make a physical model for a Maxwell fluid. Exact solutions of the non-dimensional temperature and velocity fields for Caputo and Caputo–Fabrizio time-fractional derivatives are determined via the Laplace transform technique. Numerical solutions of partial differential equations are obtained by employing Tzou’s and Stehfest’s algorithms to compare the results of both models. Exact solutions with integer-order derivative (fractional parameter α = 1) are also obtained for both temperature and velocity distributions as a special case. A graphical illustration is made to discuss the effect of Prandtl number Pr and time t on the temperature field. Similarly, the effects of Maxwell fluid parameter λ and other flow parameters on the velocity field are presented graphically, as well as in tabular form.

Hydroelastic Motion of Aircushion Type Large Floating Structures With Several Aircushions Using a Three-Dimensional Theory

2009 ◽  
Author(s):  
Tomoki Ikoma ◽  
Koichi Masuda ◽  
Chang-Kyu Rheem ◽  
Hisaaki Maeda ◽  
Mayumi Togane
Keyword(s):  
Theoretical Calculations ◽  
Three Dimensional ◽  
Prediction Method ◽  
Free Water ◽  
Bending Moment ◽  
Linear Potential ◽  
Floating Structures ◽  
Wide Wavelength Range ◽  
Linear Potential Theory ◽  
Vertical Bending Moment

This paper describes hydroelastic motion and effect of motion reduction of aircushion supported large floating structures. Motion reduction effects due to presence of aircushions have been confirmed from theoretical calculations with the zero-draft assumption. A three-dimensional prediction method has been developed for considering draft influence of division walls of aircushions. It is investigated that hydroelastic motion reduction is possible or not by using the three-dimensional theoretical calculations. In addition, the aircushion types are supported by many aircushions which are small related to wavelengths. The Green’s function method is applied to the prediction method with the linear potential theory in which effect of free water surfaces within aircushions are considered. Hydroelastic responses are estimated as not only elastic motion but also a vertical bending moment. From the results, the response reduction is confirmed, in particular, to the vertical bending moment in wide wavelength range and in whole structure area.

Wind Effects on Sloshing of a Floating Roof in a Cylindrical Liquid Storage Tank

2008 ◽  
Author(s):  
Tetsuya Matsui ◽  
Yasushi Uematsu ◽  
Koji Kondo ◽  
Takuo Wakasa ◽  
Takashi Nagaya
Keyword(s):  
Storage Tank ◽  
Wind Tunnel Test ◽  
Dynamic Interaction ◽  
Measured Data ◽  
Wind Pressure ◽  
Wind Loads ◽  
Linear Potential ◽  
Liquid Storage ◽  
Liquid Storage Tank ◽  
Linear Potential Theory

Sloshing of a floating roof in an open-topped cylindrical liquid storage tank under wind loads is investigated analytically. Wind tunnel test in a turbulent boundary layer is carried out to measure the wind pressure distributing over the roof surface. The measured data for the wind pressure is then utilized to predict the wind-induced dynamic response of the floating roof, which is idealized herein as an isotropic elastic plate of uniform stiffness and mass. The dynamic interaction between the liquid and the floating roof is taken into account exactly within the framework of linear potential theory. Numerical results are presented which illustrate the significant effect of wind loads on the sloshing response of the floating roof.

A STUDY ABOUT THE SOLUTIONS OF SCHRÖDINGER EQUATION WITH AN ASYMPTOTICALLY LINEAR POTENTIAL

1996 ◽  
Vol 11 (03) ◽  
pp. 207-209 ◽  
Author(s):  
ELSO DRIGO FILHO
Keyword(s):  
Quantum Mechanics ◽  
Schrödinger Equation ◽  
Analytical Solutions ◽  
Schrodinger Equation ◽  
Numerical Solutions ◽  
Expansion Method ◽  
Linear Potential ◽  
Asymptotically Linear

We determine the solutions of the Schrödinger equation for an asymptotically linear potential. Analytical solutions are obtained by superalgebra in quantum mechanics and we establish when these solutions are possible. Numerical solutions for the spectra are obtained by the shifted 1/N expansion method.

Improvement of Wave Power Take-Off Performance due to the Projecting Walls for OWC Type WEC

2013 ◽  
Author(s):  
Tomoki Ikoma ◽  
Koichi Masuda ◽  
Hikaru Omori ◽  
Hiroyuki Osawa ◽  
Hisaaki Maeda
Keyword(s):  
Prediction Method ◽  
Air Pressure ◽  
Wave Power ◽  
Linear Potential ◽  
Oscillating Water Column ◽  
Air Chamber ◽  
Pressure Water ◽  
Linear Potential Theory ◽  
Hydrodynamic Behaviors ◽  
Water Elevation

This paper describes a method in order to improve the performance of the primary conversion of wave power take-off. A corresponding wave energy convertor (WEC) is an oscillating water column (OWC) type. The method of the improvement has been proposed and its usefulness has been confirmed in past researches. In the method, projecting walls were attached onto front of inlet-outlet of OWC. The prediction method of hydrodynamic behaviors for the projecting walls installed OWC type WEC is explained in the paper. The boundary element method with the Green’s function is applied and influence of air pressure and free surface within every an air-chamber was directly taken into consideration in the prediction method based on a linear potential theory. Validity of the prediction method was proved comparing with results of model experiments. Series calculations are performed with the prediction method. Behaviors of air pressure, water elevation and the efficiency of primary conversion of wave power are investigated. From the calculations, length of the projecting walls was shown to affect the efficiency of primary conversion. It was available to equip the projecting walls for the improvement in oblique waves to beam sea condition as well as head sea condition. As well as only the projecting walls, application and effects of the end walls with the slit were investigated in the paper. The end walls were very useful to improve the efficiency.

Linear potential theory of steady internal supersonic flow with quasi-cylindrical geometry. Part 1. Flow in ducts

1994 ◽  
Vol 281 ◽  
pp. 159-191 ◽  
Author(s):  
Andreas Dillmann
Keyword(s):  
Supersonic Flow ◽  
Potential Theory ◽  
Broad Class ◽  
Three Dimensional ◽  
Double Series ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Linear Potential ◽  
Linear Potential Theory ◽  
Initial Boundary Value

Based on linear potential theory, the general three-dimensional problem of steady supersonic flow inside quasi-cylindrical ducts is formulated as an initial-boundary-value problem for the wave equation, whose general solution arises as an infinite double series of the Fourier–Bessel type. For a broad class of solutions including the general axisymmetric case, it is shown that the presence of a discontinuity in wall slope leads to a periodic singularity pattern associated with non-uniform convergence of the corresponding series solutions, which thus are unsuitable for direct numerical computation. This practical difficulty is overcome by extending a classical analytical method, viz. Kummer's series transformation. A variety of elementary flow fields is presented, whose complex cellular structure can be qualitatively explained by asymptotic laws governing the propagation of small perturbations on characteristic surfaces.

Sign in / Sign up

Export Citation Format

Share Document