Hydroelastic analysis of water impact of flexible asymmetric wedge with an oblique speed

Izadi, Mohammad; Ghadimi, Parviz; Fadavi, Manouchehr; Tavakoli, Sasan

doi:10.1007/s11012-018-0846-y

Cited by 29 publications

(3 citation statements)

References 65 publications

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“…[27][28][29][30][31]. In the case that the planing problem is non-linear and the fluid flow is strongly turbulent, large errors in the prediction of the performance of a planing vessel can occur when an ideal fluid hypothesis is used [32,33].…”

Section: Steady Planing Phenomenonmentioning

confidence: 99%

Performance Prediction of a Hard-Chine Planing Hull by Employing Different CFD Models

Hosseini

Tavakoli

Dashtimanesh

et al. 2021

JMSE

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This paper presents CFD (Computational Fluid Dynamics) simulations of the performance of a planing hull in a calm-water condition, aiming to evaluate similarities and differences between results of different CFD models. The key differences between these models are the ways they use to compute the turbulent flow and simulate the motion of the vessel. The planing motion of a vessel on water leads to a strong turbulent fluid flow motion, and the movement of the vessel from its initial position can be relatively significant, which makes the simulation of the problem challenging. Two different frameworks including k-ε and DES (Detached Eddy Simulation) methods are employed to model the turbulence behavior of the fluid motion of the air–water flow around the boat. Vertical motions of the rigid solid body in the fluid domain, which eventually converge to steady linear and angular displacements, are numerically modeled by using two approaches, including morphing and overset techniques. All simulations are performed with a similar mesh structure which allows us to evaluate the differences between results of the applied mesh motions in terms of computation of turbulent air–water flow around the vessel. Through quantitative comparisons, the morphing technique has been seen to result in smaller errors in the prediction of the running trim angle at high speeds. Numerical observations suggest that a DES model can modify the accuracy of the morphing mesh simulations in the prediction of the trim angle, especially at high-speeds. The DES model has been seen to increase the accuracy of the model in the computation of the resistance of the vessel in a high-speed operation, as well. This better level of accuracy in the prediction of resistance is a result of the calculation of the turbulent eddies emerging in the water flow in the downstream zone, which are not captured when a k-ε framework is employed. The morphing approach itself can also increase the accuracy of the resistance prediction. The overset method, however, overpredicts the resistance force. This overprediction is caused by the larger vorticity, computed in the direction of the waves, generated under the bow of the vessel. Furthermore, the overset technique is observed to result in larger hydrodynamic pressure on the stagnation line, which is linked to the greater trim angle, predicted by this approach. The DES model is seen to result in extra-damping of the second and third crests of transom waves as it calculates the stronger eddies in the wake of the boat. Overall, a combination of the morphing and DES models is recommended to be used for CFD modeling of a planing hull at high-speeds. This combined CFD model might be relatively slower in terms of computational time, but it provides a greater level of accuracy in the performance prediction, and can predict the energy damping, developed in the surrounding water. Finally, the results of the present paper demonstrate that a better level of accuracy in the performance prediction of the vessel might also be achieved when an overset mesh motion is used. This can be attained in future by modifying the mesh structure in such a way that vorticity is not overpredicted and the generated eddies, emerging when a DES model is employed, are captured properly.

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Section: Steady Planing Phenomenonmentioning

confidence: 99%

Performance Prediction of a Hard-Chine Planing Hull by Employing Different CFD Models

Hosseini

Tavakoli

Dashtimanesh

et al. 2021

JMSE

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“…The main difference between these studies lies in the physics involved. For example, Izadi et al (2018) presented fluid motion around an elastic body entering the water with an oblique speed, showing that elastic motions on two sides of the body entering water are very different, and affect the impact pressure in different ways.…”

Section: Introductionmentioning

confidence: 99%

A fluid–solid momentum exchange method for the prediction of hydroelastic responses of flexible water entry problems

2023

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The paper presents a Fluid Structure Interaction (FSI) method for hydroelastic water entry. The method assumes that the momentum exchange between the fluid and solid body can be used for the calculation of pressure, deformation and stresses arising during impact. The flexible fluid–structure interactions of flat plates entering water are solved using a computational code that employs the finite volume method to discretise both fluid and solid equations. This provides a better matching of momentum on the fluid–solid interface. The momentum arising in the solid body that emerges after the impact is defined as the momentum exchange, and is shown to increase linearly under the increase of non-dimensional impact speed. The ratio of the maximum pressure arising in an elastic body entering water to that of a rigid body is termed relative pressure and is shown to decrease linearly as a function of momentum exchange. The latter verifies the main hypothesis of this paper, namely that ‘the pressure acting on an elastic body can be predicted using an unsophisticated equation that uses the momentum exchange.’ The deformation and stresses arising in elastic plates entering water are demonstrated to be functions of momentum exchange and can be found using simple equations formulated via parametrisation of data. It is concluded that subject to further validation, the method could be extended for the prediction of hydroelastic response of other sections/bodies entering water.

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“…Systematic experimental studies of the stepped planing hull series have been conducted by Morabito et al, 3 Lee et al, 4 Ma et al 11 and Taunton et al 12 Besides the mentioned experimental studies, mathematical models have also been used to model nonstepped/stepped planing hulls. 13,14 Some of these mathematical methods have been established by using the 2D + T method, where the results of water entry of a wedge [15][16][17] are used to simulate motion of planing hulls in both calm water and waves (see, for example, Tavakoli et al, 14 Tavakoli and Dashtimanesh 15 and Ghadimi and colleagues [18][19][20][21] ). The 2D + T method has even shown the ability to model yawed planing motion 15,22,23 and has been recently used to model stepped boats by Niazmand Bilandi et al 24 In addition to this model, the theoretical simulations of Matveev 25 have been used for modeling of the flow around stepped planing ships.…”

Section: Introductionmentioning

confidence: 99%

Effects of step configuration on hydrodynamic performance of one- and doubled-stepped planing flat plates: A numerical simulation

Dashtimanesh

Roshan

Tavakoli

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part M:

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Categorized as one of high-speed marine vehicles, stepped planing hulls have the potential to reach relatively high speed in the sea by decreasing wetted surface. There were and still are some challenges in modeling of these vessels and design of ideal situation of steps. In the current study, a numerical-based method has been used to provide understanding about the effect of step height and its location on hydrodynamic characteristics of double-stepped planing plates. At the first step, one-stepped planing plate is numerically simulated. Results are compared against exiting numerical data, suggesting that results of the current numerical simulation are similar to results of previous numerical simulations. Then, double-stepped planing plates are modeled and pressure distribution, wetted length, free surface elevation and drag over lift ratio are computed. It is seen that, ventilation length behind the step and pressure coefficient are increased when step height of one- and a double-stepped planing plates are increased. It has been shown that, unlike an one-stepped planing plate, drag coefficient of a double-stepped planing plate can be increased when the step height is increased. The effects of the location of the second step on the performance of the planing plate have been explored, showing that this position plays a critical role on hydrodynamic forces. It is demonstrated that when the smallest possible lift force is produced by the middle-body, the plate shows the best performance (highest lift over drag ratio).

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Hydroelastic analysis of water impact of flexible asymmetric wedge with an oblique speed

Cited by 29 publications

References 65 publications

Performance Prediction of a Hard-Chine Planing Hull by Employing Different CFD Models

Performance Prediction of a Hard-Chine Planing Hull by Employing Different CFD Models

A fluid–solid momentum exchange method for the prediction of hydroelastic responses of flexible water entry problems

Effects of step configuration on hydrodynamic performance of one- and doubled-stepped planing flat plates: A numerical simulation

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