Hydrodynamic force and attitude angle characteristics of a spinning stone impacting a free surface

2021 ◽  
Vol 33 (12) ◽  
pp. 123309
Author(s):  
Conghui Li ◽  
Cong Wang ◽  
Yingjie Wei ◽  
Weixue Xia ◽  
Chengju Zhang
Keyword(s):  
Free Surface ◽  
Hydrodynamic Force ◽  
Attitude Angle

scholarly journals HYDRODYNAMIC FORCE EXERTING ON A SQURE PILLAR IN STEADY FREE SURFACE SHEAR FLOWS

2002 ◽  
Vol 46 ◽  
pp. 827-832
Author(s):  
Juichiro AKIYAMA ◽  
Mirei SHIGE-DA ◽  
Toshihiko KOBAYASHI ◽  
Kazumasa OOTA
Keyword(s):  
Free Surface ◽  
Shear Flows ◽  
Hydrodynamic Force ◽  
Surface Shear

scholarly journals Experimental Method for the Measurements and Numerical Investigations of Force Generated on the Rotating Cylinder under Water Flow

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2216
Author(s):  
Teresa Abramowicz-Gerigk ◽  
Zbigniew Burciu ◽  
Jacek Jachowski ◽  
Oskar Kreft ◽  
Dawid Majewski ◽  
...  
Keyword(s):  
Free Surface ◽  
Experimental Test ◽  
Surface Effect ◽  
Hydrodynamic Force ◽  
Velocity Ratio ◽  
Rotating Cylinder ◽  
Diameter Ratio ◽  
Water Current ◽  
Test Setup ◽  
Length To Diameter Ratio

The paper presents the experimental test setup and measurement method of hydrodynamic force generated on the rotating cylinder (rotor) under uniform flow including the free surface effect. The experimental test setup was a unique construction installed in the flume tank equipped with advanced flow generating and measuring systems. The test setup consisted of a bearing mounted platform with rotor drive and sensors measuring the hydrodynamic force. The low length to diameter ratio cylinders were selected as models of bow rotor rudders of a shallow draft river barge. The rotor dynamics was tested for the rotational speeds up to 550 rpm and water current velocity up to 0.85 m/s. The low aspect ratio of the cylinder and free surface effect had significant impacts on the phenomena influencing the generated hydrodynamic force. The effects of the rotor length to diameter ratio, rotational velocity to flow velocity ratio, and the Reynolds number on the lift force were analyzed. The validation of the computational model against experimental results is presented. The results show a similar trend of results for the simulation and experiment.

Free-surface flow due to impulsive motion of a submerged circular cylinder

1995 ◽  
Vol 286 ◽  
pp. 67-101 ◽  
Author(s):  
Peder A. Tyvand ◽  
Touvia Miloh
Keyword(s):  
Free Surface ◽  
Circular Cylinder ◽  
Hydrodynamic Force ◽  
Free Surface Flow ◽  
Small Time ◽  
Surface Flow ◽  
Constant Acceleration ◽  
Impulsive Motion ◽  
Gravitational Effects ◽  
Bipolar Coordinates

The impulsively starting motion of a circular cylinder submerged horizontally below a free surface is studied analytically using a small-time expansion. The series expansion is taken as far as necessary to include the leading gravitational effects for two cases: constant velocity and constant acceleration, both commencing from rest. The hydrodynamic force on the cylinder and the surface elevation are calculated and expressed in terms of bipolar coordinates. Comparisons are also made with earlier theoretical and experimental work. The theory is valid for arbitrary value of submergence depth to cylinder radius.

Unsteady Stokes Flow for a Vibrating Cantilever Under a Free-Surface

2014 ◽  
Author(s):  
Giovanni Di Ilio ◽  
Iskender Sahin ◽  
Angelantonio Tafuni
Keyword(s):  
Free Surface ◽  
Hydrodynamic Force ◽  
Rectangular Cross Section ◽  
Damping Coefficients ◽  
Particle Hydrodynamics ◽  
Unsteady Stokes Flow ◽  
Smoothed Particle ◽  
Parametric Studies ◽  
Stress Free Boundary ◽  
Quiescent Fluid

Vibration of a thin, rectangular-cross-section beam submerged in a viscous, quiescent fluid undergoing small amplitude oscillations is studied using a Boundary Element (BE) approach in which the free-surface is modeled through a stress-free boundary condition. The Stokes approximation is used where nonlinear convective terms are negligible and the problem is formulated in Fourier and Laplace transform space when appropriate. Results are expressed in terms of non-dimensional hydrodynamic force and its components, namely added mass and damping coefficients. Several parametric studies are conducted to evaluate the effects of depth of submergence, frequency and the amplitude of oscillations on the hydrodynamic functions. The results are compared with the classical solution for a vibrating lamina in an infinite fluid as the limit case and with a recent study using Smoothed Particle Hydrodynamics (SPH) analysis in the presence of a free-surface.

Free-surface flow generated by a small submerged circular cylinder starting from rest

1995 ◽  
Vol 286 ◽  
pp. 103-116 ◽  
Author(s):  
Peder A. Tyvand ◽  
Touvia Miloh
Keyword(s):  
Free Surface ◽  
Circular Cylinder ◽  
Hydrodynamic Force ◽  
Free Surface Flow ◽  
Small Time ◽  
Surface Flow ◽  
Third Order ◽  
Force Prediction ◽  
Small Cylinder ◽  
Submergence Depth

The impulsively starting motion of a small circular cylinder submerged horizontally below a free surface is studied analytically using a small-time expansion. The cylinder is considered small if the ratio between its radius and initial submergence depth is much smaller than one. The surface elevation is calculated up to third order. The hydrodynamic force on the small cylinder is also discussed. Certain inconsistencies in our small-cylinder approximation (assuming locally uniform flow around the cylinder) are found in the force prediction. The present work is an accompanying paper to Tyvand & Miloh (1995), where the same problem is studied for arbitrary radius versus submergence depth.

Hydrodynamic Loads on Vibrating Cantilevers Under a Free Surface in Viscous Fluids With SPH

2013 ◽  
Author(s):  
Angelantonio Tafuni ◽  
Iskender Sahin
Keyword(s):  
Free Surface ◽  
Hydrodynamic Force ◽  
Finite Amplitude ◽  
Viscous Fluids ◽  
Periodic Force ◽  
Thin Beam ◽  
Fluid Field ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Phase Lags

Smoothed Particle Hydrodynamics (SPH) based simulations are implemented to study finite amplitude vibrations of a submerged cantilever beam in viscous fluids under a free surface. The cross section of a thin beam is modelled as a rectangular 2D oscillating rigid lamina, around which fluid field properties are computed. The study is carried out using non-dimensional frequency, amplitude of oscillations and depth of submergence. The total hydrodynamic force on the vibrating beam is extracted via SPH analysis, together with the contours of fluid field properties. Comparison is made between the results obtained with and without the free surface. We find that the presence of the free surface strongly influences the flow physics around the lamina, giving rise to non-harmonic velocity profiles and non-periodic force responses, coupled with phase lags and non-zero mean force during periodic oscillations.

Modeling Issues Related to the Hydrodynamics of Three-Dimensional Steady Planing

1995 ◽  
Vol 39 (01) ◽  
pp. 1-24
Author(s):  
Canhai Lai ◽  
Armin W. Troesch
Keyword(s):  
Free Surface ◽  
High Speed ◽  
Vortex Lattice ◽  
Hydrodynamic Force ◽  
Near Field ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Pressure Condition ◽  
General Shape ◽  
Pressure Distributions

A three-dimensional numerical model using vortex lattice methods is developed to solve the steady planing problem. This paper examines assumptions related to high-speed planing hydrodynamics, including those used by two-dimensional slender-body theories. Emphasis is placed upon the investigation of various modeling issues such as the zero pressure condition on the free surface and the treatment of the flow off the chines. Numerical results including hydrodynamic forces and pressure distributions are presented and compared with experiments. A simple model to include the effect of gravity in the near field is also examined. The models described here can be incorporated into design methodologies for predicting the hydrodynamic force and moment acting on planing hulls with general shape.

scholarly journals HYDRODYNAMIC FORCE EXERTING ON A SQURE PILLAR IN UNSTEADY FREE SURFACE FLOWS

2002 ◽  
Vol 46 ◽  
pp. 1205-1210 ◽  
Author(s):  
Juichiro AKIYAMA ◽  
Mirei SHIGE-DA ◽  
Toshihiko KOBAYASHI ◽  
Kazumasa OOTA
Keyword(s):  
Free Surface ◽  
Hydrodynamic Force ◽  
Free Surface Flows ◽  
Surface Flows

scholarly journals Hydrodynamic Force on the Vertical Wall of a Portable Water Storage Tank: Nonlinear Peregrine Model

2020 ◽  
Vol 20 (4) ◽  
pp. 121-126
Author(s):  
Jinsoo Park ◽  
Soohyun So ◽  
Taek Soo Jang
Keyword(s):  
Free Surface ◽  
Nonlinear Model ◽  
Structural Design ◽  
Storage Tank ◽  
Hydrodynamic Force ◽  
Vertical Wall ◽  
Water Storage ◽  
Basic Data ◽  
Water Storage Tank ◽  
Run Up

In this study, the motion of free-surface generated by vertically dropping water through a nozzle into a portable water storage tank with a convex bottom in calm conditions was numerically simulated using the nonlinear Peregrine model. The hydrodynamic force at the vertical wall was calculated after measuring the maximum run-up amplitude of the free-surface. The degree of improvement of the results using a nonlinear model was identified by its comparison with numerical results using the linear Peregrine model. Finally, it is expected that the hydrodynamic forces on the vertical wall of the storage tank with a convex bottom can be reduced to a certain extent compared to the concave bottom and can therefore be utilized as basic data for the structural design of an ideal storage tank.

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