Hydrodynamic force acted on a solid translating in nonuniform stream

Lipid vesicles, especially giant lipid vesicles (GLVs), are usually adopted as cell membrane models and their preparation has been widely studied. However, the effects of some nonelectrolytes on GLV formation have not been specifically studied so far. In this paper, the effects of the nonelectrolytes, including sucrose, glucose, sorbitol and ethanol, and their coexistence with sodium chloride, on the lipid hydration and GLV formation were investigated. With the hydration method, it was found that the sucrose, glucose and sorbitol showed almost the same effect. Their presence in the medium enhanced the hydrodynamic force on the lipid membranes, promoting the GLV formation. GLV formation was also promoted by the presence of ethanol with ethanol volume fraction in the range of 0 to 20 percent, but higher ethanol content resulted in failure of GLV formation. However, the participation of sodium chloride in sugar solution and ethanol solution stabilized the lipid membranes, suppressing the GLV formation. In addition, the ethanol and the sodium chloride showed the completely opposite effects on lipid hydration. These results could provide some suggestions for the efficient preparation of GLVs.

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Hydrodynamic force on circular cylinders

Applied Ocean Research ◽

10.1016/s0141-1187(86)80014-1 ◽

1986 ◽

Vol 8 (3) ◽

pp. 151-155 ◽

Cited By ~ 9

Author(s):

Ole Secher Madsen

Keyword(s):

Hydrodynamic Force ◽

Circular Cylinders

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A Hybrid Numerical Framework for Simulation of Ships Maneuvering in Waves

Journal of Ship Research ◽

10.5957/josr.06200037 ◽

2021 ◽

pp. 1-13

Author(s):

Paul F. White ◽

Dominic J. Piro ◽

Bradford G. Knight ◽

Kevin J. Maki

Keyword(s):

Hydrodynamic Force ◽

Linear Time ◽

Domain Boundary ◽

Critical Role ◽

Force Model ◽

Efficient Computation ◽

Fast Running ◽

Surface Ship ◽

Calm Water ◽

Maneuvering In Waves

The maneuvering characteristics of a surface ship play a critical role in the safety of navigation both in port and in an open seaway, and are vital to the overall operational ability of the ship. The vast majority of maneuvering analyses for ships have been performed under the assumption of calm water, yet ships mostly operate in waves. Understanding of maneuvering in waves is limited by the complexity of the problem and the challenges of performing physical experiments and numerical simulations. In this work, a new fast-running method that allows for the study of maneuvering in waves is formulated. The newly formulated approach is categorized as a “hybrid method,” taking its name from the multiple numerical methods and force models used to predict the total hydrodynamic force acting on the vessel maneuvering in waves. The framework presented here uses a combination of Computational Fluid Dynamics, a linear time-domain boundary element method, and a propeller-force model for efficient computation of the total hydrodynamic force.

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FUNDAMENTAL ANALYSIS OF THREE-DIMENSIONAL ‘NEAR FLING’

Journal of Experimental Biology ◽

10.1242/jeb.183.1.217 ◽

1993 ◽

Vol 183 (1) ◽

pp. 217-248 ◽

Cited By ~ 8

Author(s):

S. Sunada ◽

K. Kawachi ◽

I. Watanabe ◽

A. Azuma

Keyword(s):

Numerical Calculation ◽

Hydrodynamic Force ◽

Dynamic Pressure ◽

Three Dimensional ◽

Added Mass ◽

Opening Angle ◽

Rotation Axes ◽

Adequate Accuracy ◽

Series Of Experiments ◽

The Moment

A series of experiments on three-dimensional ‘near fling’ was carried out. Two pairs of plates, rectangular and triangular, were selected, and the distance between the rotation axes of the two plates of each pair was varied. The motion of the plates as well as the forces and the moment were measured, and the interference between the two plates of a pair was studied. In addition, a method of numerical calculation was developed to aid in the understanding of the experimental results. The interference between the two plates of a pair, which acted to increase both the added mass of each plate and the hydrodynamic force due to dynamic pressure, was noted only when the opening angle between the plates was small. The hydrodynamic forces were strongly influenced by separated vortices that occurred during the rotation. A method of numerical calculation, which took into account the effect both of interference between the plates and of separated vortices, was developed to give adequate accuracy in analyzing beating wings in ‘near fling’.

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Wall Effects On the Flow Dynamics of a Rigid Sphere in Motion

Journal of Fluids Engineering ◽

10.1115/1.4051215 ◽

2021 ◽

Author(s):

Zhi-gang Feng ◽

Jason Gatewood ◽

E.E. Michaelides

Keyword(s):

Hydrodynamic Force ◽

Rotational Velocity ◽

Analytical Data ◽

Particle Diameter ◽

Immersed Boundary ◽

Rigid Sphere ◽

Wall Effects ◽

Falling Sphere ◽

Dimensionless Ratio ◽

Free Falling

Abstract The presence of a wall near a rigid sphere in motion is known to disturb the particle fore and aft flow field symmetry and to affect the hydrodynamic force. An Immersed Boundary Direct Numerical Simulation (IB-DNS) is used in this study to determine the wall effects on the dynamics of a free-falling sphere and the drag of a sphere moving at a constant velocity. The numerical results are validated by comparison to the published experimental, numerical, and analytical data. The pressure and velocity fields are numerically computed when the particle is in the vicinity of the wall; the transverse (lift) and longitudinal (drag) parts of the hydrodynamic force are calculated; its rotational velocity is also investigated in the case of a free-falling sphere. The flow asymmetry also causes the particle to rotate. The wall effect is shown to be significant when the dimensionless ratio of the wall distance to the particle diameter, L/D, is less than 3. The wall effects are more pronounced and when the particle Reynolds number, Re, is less than 10. Based on the computational results, a useful correlation for the wall effects on the drag coefficients spheres is derived in the range 0.75 < L/D < 3 and 0.18 < Re < 10.

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