Unsteady free surface flow above a moving circular cylinder

Kostikov, Vasily; Makarenko, N. G.

doi:10.1007/s10665-018-9962-x

Cited by 5 publications

(22 citation statements)

References 19 publications

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“…To validate the numerical implementation we analyse the submersion of a cylinder under constant acceleration. This case has been explored previously by several authors (see Tyvand & Miloh 1995; Makarenko 2003; Kostikov & Makarenko 2018) and therefore provides a good testing ground for verifying the results of the present numerical model. In these works it is demonstrated that the odd-numbered orders () are zero for submersions under constant acceleration, which reduces the computational cost compared with other submersion profiles.…”

Section: Basic Equationsmentioning

confidence: 79%

“…Under these restrictions, prescribing the submersion profile suffices to completely describe the motion of the cylinder. The influence of the direction of motion on the surface perturbations can be readily found elsewhere in the works by Tyvand & Miloh (1995) and by Kostikov & Makarenko (2018).…”

Section: Basic Equationsmentioning

confidence: 86%

“…To compute the surface profile , one needs to reduce all the equations to variables defined only on the free surface. We start by introducing the tangential and normal velocities at the free surface, as follows: The surface equations in terms of these variables are obtained from the method by Kostikov & Makarenko (2018), which will be employed and expanded upon. Appendix A presents the derivation by Kostikov & Makarenko (2018) of the system of differential equations and of the real-valued integral equation where the Cauchy principal values (p.v.)…”

Section: Basic Equationsmentioning

confidence: 99%

“…Approximate analytical expressions have been obtained by Kostikov & Makarenko (2018). The equations for the two non-zero leading perturbation orders in the case of an obstacle under motion of constant acceleration are (Kostikov & Makarenko 2018) with functions and , and being the anticlockwise angle of the initial velocity relative to the horizontal axis. In a different work, Tyvand & Miloh (1995) solved the second- and fourth-order contributions for constant acceleration.…”

Section: Basic Equationsmentioning

confidence: 99%

“…(1985) and based on the Wehausen scheme, transforms the problem to a boundary integro-differential system of equations defined only on the free surface. Kostikov & Makarenko (2018) obtained analytical expressions for the temporal development of free-surface perturbations valid to the fourth order in space, relative to the radius of the submerging cylinder.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Free-surface disturbances due to the submersion of a cylindrical obstacle

Pardo

Nedic

2021

J. Fluid Mech.

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We explore the initial perturbations that form on a liquid free surface as a result of the submersion of a circular cylinder beneath the surface, a scenario that arises in a number of diverse applications. The behaviour of the free surface is determined by transforming the equations of motion of the system via the Wehausen scheme, to variables for the free surface. A small-time series expansion is utilized to construct a recursive scheme that can be implemented numerically, and the time frame over which this approximation is valid is analysed. The resulting numerical model allows one to extend the results in the literature to study arbitrary cylinder sizes, including those where the cylinder is close to the free surface, and arbitrary cylinder motions. Of particular interest in this study was identifying the conditions under which strong jets would appear, and those were the free surface exhibited gravity waves. The formation of a central jet is found to be related to the growth of secondary, nonlinear waves, which rapidly merge as the obstacle is submerged. Classification maps are presented as a function of obstacle size and submersion speed, to identify the conditions which lead to jetting. Furthermore, the acceleration profile of the cylinder is shown to significantly affect the conditions under which jets form, which we argue is due to the rate at which energy is injected into the system.

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Section: Basic Equationsmentioning

confidence: 79%

Section: Basic Equationsmentioning

confidence: 86%

Section: Basic Equationsmentioning

confidence: 99%

Section: Basic Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Free-surface disturbances due to the submersion of a cylindrical obstacle

Pardo

Nedic

2021

J. Fluid Mech.

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Jetting onset on a liquid surface accelerated past a submerged cylinder

Pardo

Barua²,

Lisak³

et al. 2022

Flow

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A novel experiment is presented to study the initial disturbances on a free surface due to the constant acceleration of liquid around a submerged obstacle. The surface response to different obstacle sizes, initial surface heights and fluid velocities is measured using high-speed videography. Perturbations observed on the surface are classified into either jetting or gravity waves by measuring the steepness of growing liquid columns. A classification phase map between these two regimes is obtained and compared with analytical results by Martín Pardo and Nedić (2021). The agreement between decision boundaries is good for high Froude numbers (high fluid velocities) but deteriorates at lower velocities, where viscosity and surface tension effects (not considered in the analytical model) have a greater predominance. The surface profile and perturbation amplitude measured in experiments are also compared against this analytical model. In all cases, the model accurately predicts the corresponding experimental results at the beginning of the motion, but the prediction error increases with time. It is also observed that faster moving surfaces that lead to the onset of jetting have greater prediction accuracies and longer validity times of the predictions.

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Impulsive impact of a body fully submerged in an open container

Savchenko

et al. 2023

J. Fluid Mech.

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An impulsively starting motion of a cylindrical body submerged below a calm water surface in an open container of arbitrary shape is considered. This work generalizes the case of an infinite-depth liquid studied by Semenov et al. (J. Fluid Mech., vol. 919, 2021, R4). Particular attention is paid to the interaction between the body, the free surface and the container. The integral hodograph method is employed to derive the complex velocity potential in a parameter plane. The boundary-value problem is reduced to a system of integral equations, which is solved numerically. The velocity field, the pressure impulse on the body and the container wall and the added mass just after the impact are determined for a wide range of depths of submergence and container geometries and for various cross-sectional shapes of the body, such as a flat plate, a circle and a rectangle.

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Unsteady free surface flow above a moving circular cylinder

Cited by 5 publications

References 19 publications

Free-surface disturbances due to the submersion of a cylindrical obstacle

Free-surface disturbances due to the submersion of a cylindrical obstacle

Jetting onset on a liquid surface accelerated past a submerged cylinder

Impulsive impact of a body fully submerged in an open container

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