Variational generalization of the Green–Naghdi and Whitham equations for fluid sloshing in three-dimensional rotating and translating coordinates

2021 ◽  
Author(s):  
Hamid Alemi Ardakani
Keyword(s):  
Three Dimensional ◽  
Fluid Sloshing ◽  
Whitham Equations

Numerical Simulation of VLEC Hydrodynamic Response Coupled with Tank Sloshing

2015 ◽  
Author(s):  
Zhou Qinghua ◽  
Li Xiaoling ◽  
Yang Qi ◽  
B. Qin
Keyword(s):  
Three Dimensional ◽  
Ship Motion ◽  
Movement Behavior ◽  
Structural Safety ◽  
Navier Stokes ◽  
Linear Potential ◽  
Fluid Sloshing ◽  
Response Amplitude Operators ◽  
Cfd Method ◽  
Tank Sloshing

The coupling effects of tank sloshing on the ship motion and wave-induced loads of a very large ethane carrier (VLEC) with 83000m3 loading capacity and four membrane tanks are systematically investigated. The ship motion equation coupled with tank sloshing is calculated in the frequency domain based on three dimensional linear potential flow theory. The added mass, damping coefficient and restoring stiffness correction due to tank sloshing are considered. The response amplitude operators (RAO) of ship motion and sectional loads with and without considering tank sloshing are obtained. Taking ship motion dynamic response as excitation input condition, the three dimensional fluid sloshing movement behavior and sloshing-induced impact pressure are simulated by the computational fluid dynamics (CFD) method. The Renormalized Group (RNG) k-ε turbulence model is selected and used with the Reynolds-Averaged Navier-Stokes (RANS) equation; the volume of fluid method is adopted to predict the free surface elevation. The results provide valuable references for the overall design and structural safety assessment of VLEC.

Attitude-Adjustment-Induced Sloshing Characteristics in a Satellite Propellant Tank

2012 ◽  
Vol 28 (2) ◽  
pp. 261-268 ◽  
Author(s):  
A.-S. Yang
Keyword(s):  
Piecewise Linear ◽  
Three Dimensional ◽  
Surface Force ◽  
Fluid Sloshing ◽  
Attitude Adjustment ◽  
Attitude Modification ◽  
Performance Deterioration ◽  
Propellant Tank ◽  
The Impact ◽  
The Continuum

AbstractThe fluid sloshing behavior in a propellant tank is a major concern for the control and stabilization of a spacecraft. This research aims to investigate the attitude-adjustment-induced sloshing phenomenon in a satellite propellant tank under microgravities. In the analysis, the complicated interfacial flow was simulated using the transient three-dimensional conservation equations of mass and momentum with treatment of the surface tension effect at the interface boundary by the continuum surface force (CSF) model. The volume-of-fluid (VOF) method in conjunction with the piecewise linear interface construction (PLIC) technique was also utilized to describe the fluid interface motions. Computations were performed to simulate the sloshing process in the FORMOSAT-2 propellant tank for determining the impact disturbance properties generated during the pitch maneuver. Because the predicted disturbance moments were well below the design control moments, the attitude-adjustment-induced sloshing effect would not cause any performance deterioration for satisfactory attitude modification of the satellite.

A variational principle for three-dimensional interactions between water waves and a floating rigid body with interior fluid motion

2019 ◽  
Vol 866 ◽  
pp. 630-659 ◽  
Author(s):  
Hamid Alemi Ardakani
Keyword(s):  
Variational Principle ◽  
Rigid Body ◽  
Water Waves ◽  
Fluid Motion ◽  
Three Dimensional ◽  
Rigid Body Dynamics ◽  
The Body ◽  
Three Dimensions ◽  
Fluid Sloshing ◽  
Gravity Driven

A variational principle is given for the motion of a rigid body dynamically coupled to its interior fluid sloshing in three-dimensional rotating and translating coordinates. The fluid is assumed to be inviscid and incompressible. The Euler–Poincaré reduction framework of rigid body dynamics is adapted to derive the coupled partial differential equations for the angular momentum and linear momentum of the rigid body and for the motion of the interior fluid relative to the body coordinate system attached to the moving rigid body. The variational principle is extended to the problem of interactions between gravity-driven potential flow water waves and a freely floating rigid body dynamically coupled to its interior fluid motion in three dimensions.

Attitude-pendulum-sloshing coupled dynamics of quadrotors slung liquid containers

2022 ◽  
pp. 095441002110689
Author(s):  
Kuo Zhu ◽  
Jie Huang ◽  
Sergey Gnezdilov
Keyword(s):  
Control Method ◽  
Three Dimensional ◽  
Flight Safety ◽  
Attitude Dynamics ◽  
External Disturbances ◽  
Coupled Oscillations ◽  
Aerial Vehicles ◽  
Fluid Sloshing ◽  
Sloshing Dynamics ◽  
Load Swing

Quadrotors suspended water containers may be used for fire-fighting services. Unfortunately, the complicated dynamics in this type of system degrade the flight safety because of coupling effects among the quadrotor attitude, container swing, and liquid sloshing. However, few effects have been directed at the attitude-pendulum-sloshing dynamics in this type of aerial cranes. A novel planar model of a quadrotor carrying a liquid tank under dual-hoist mechanisms is presented. The model includes vehicle-attitude dynamics, load-swing dynamics, and fluid-sloshing dynamics. Resulting from the model, a new method is proposed to control coupled oscillations among the vehicle attitude, load swing, and fluid sloshing. Numerous simulations on the nonlinear model demonstrate that the control method can reduce the undesirable oscillations, stabilize the quadrotor’s attitude, and reject the external disturbances. The theoretical findings may also extend to the three-dimensional dynamics of quadrotors slung liquid tanks, and other types of aerial vehicles transporting liquid containers including helicopters or tiltrotors.

scholarly journals Study of the effect of baffles on longitudinal stability of partly filled fuel tanker semi-trailer using CFD

2021 ◽  
Vol 3 (SI2) ◽  
pp. SI13-SI23
Author(s):  
HUYNH PHUOC THIEN ◽  
Hong Duc Thong ◽  
Tran Minh Tai
Keyword(s):  
Fluid Dynamic ◽  
Three Dimensional ◽  
Stability Limit ◽  
Longitudinal Stability ◽  
Fluid Sloshing ◽  
Transient Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
The Stability ◽  
Different Levels ◽  
Simulation Scheme

Sloshing of liquid in partially filled fuel tanker vehicles has a strong effect on the directional stability and safety performance. Under the maneuver of the vehicle, such as steering, braking, or accelerating, the liquid fuel in the tanker tends to oscillate. As a result, hydrodynamic forces and moments raise. It leads to reduce the stability limit and the controllability of the vehicle. To minimize the effect of sloshing, the baffles are usually added to the tanker. This paper presents the study of the effect of baffles on the longitudinal stability of the fuel tanker semi-trailer using the computational fluid dynamics (CFD) approach. A three-dimensional fluid dynamic model of a typical tanker with different baffle configurations is developed. The User Defined Function (UDF) is used to control the acceleration of the tanker according to the simulation scheme. Transient simulations are performed for the cases of constant acceleration longitudinal maneuvers with different levels of fuel in the tanker. The volume of fluid (VOF) and air obtained from the simulation is used to indirectly calculate the center of gravity of the tanker. The post-processing results show that the baffles could provide resistance to the fluid sloshing, resulting in an improvement of the longitudinal stability of the tanker semi-trailer. The results also prove that the benefit of the baffle to the fuel tanker vehicle’s stability depends on the size of the baffle, as well as the number of baffles. The 40% height three baffles model is the proper baffle model to resist the longitudinal sloshing in the partially filled tanker of the studied trailer. By adding baffles, shifting of load on the kingpin and the rear axis are less than 5% and 2% as the tanker is filled with 50% and 70% fluid level respectively.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Sign in / Sign up

Export Citation Format

Share Document