A Numerical Study on Dynamic Instability Motion Control of Wave-Piercing High-Speed Planing Craft in Calm Water using Side Appendages

2017 ◽  
Vol 23 (3) ◽  
pp. 320-329 ◽  
Author(s):  
Deok-Ki Kim ◽  
◽  
Won-Ju Lee ◽  
Jong-Su Kim
Keyword(s):  
Motion Control ◽  
High Speed ◽  
Dynamic Instability ◽  
Numerical Study ◽  
Planing Craft ◽  
Calm Water

Comparison between the Dynamic Behavior of the Non-stepped and Double-stepped Planing Hulls in Rough Water: A Numerical Study

2020 ◽  
Vol 36 (01) ◽  
pp. 52-66
Author(s):  
Arman Esfandiari ◽  
Sasan Tavakoli ◽  
Abbas Dashtimanesh
Keyword(s):  
Numerical Simulations ◽  
High Speed ◽  
Numerical Study ◽  
Vertical Plane ◽  
Recent Decade ◽  
Vertical Acceleration ◽  
Gravitational Acceleration ◽  
Head Waves ◽  
Calm Water ◽  
Rough Water

Reducing vertical motions of high-speed planing hulls in rough water is one of the most important factors that help a boat to become more operable, and will benefit the structure of the boat and the crew on board. In the recent decade, stepped planing hulls have been investigated with emphasis on their better performance in calm water than that of nonstepped planing hulls. However, there are still doubts about their performance in rough water. In this study, we investigate this problem by providing numerical simulations for motions of a double-stepped and a non-stepped planing hull in a vertical plane when they encounter head waves. The problem will be solved using the finite volume method and volume of fluid method. To this end, a numerical computational fluid dynamics code (STARCCM1) has been used. Accuracy of the numerical simulations is evaluated by comparing their outcome with available experimental data. The dynamic response of the investigated hulls has been numerically modeled for two different wave lengths, one of which is smaller than the boat length and the other which is larger than the boat length. Using the numerical simulations, heave and pitch motions as well as vertical acceleration are found. It has been found that at wave lengths larger than the boat length, heave amplitude decreases by 10–40%when two steps are added to the bottom of a vessel. It has also been observed that pitch of a planing hull is reduced by 18–32% in the presence of the two steps on its bottom. Finally, it has been observed that for wave lengths larger than the boat length, the maximum vertical acceleration decreases by a gravitational acceleration of about .2–.7.

Comparisons Between Prediction and Experiment for Lift Force and Heel Moment for a Planing Hull

2013 ◽  
Vol 29 (01) ◽  
pp. 36-46
Author(s):  
Carolyn Q. Judge
Keyword(s):  
High Speed ◽  
Lift Force ◽  
Forward Speed ◽  
Dynamic Effects ◽  
Planing Craft ◽  
Underwater Photography ◽  
Calm Water ◽  
Transverse Stability ◽  
The Relationship ◽  
Righting Moment

Even in calm water, high-speed vessels can display unstable behaviors such chine walking, sudden large heel, and porpoising. Large heel results from the loss of transverse stability at high forward speed. When a planing craft begins to plane, the hydrodynamic lift forces raise the hull out of the water. The available righting moment resulting from the hydrostatic buoyancy is, therefore, reduced. As the righting moment resulting from hydrostatic buoyancy is reduced, the righting moment resulting from dynamic effects becomes important. These hydrodynamic righting effects are related to the hydrodynamic lift. This article explores the relationship between the hydrostatic lift and righting moment, the hydrodynamic lift and righting moment, and the total lift and heel-restoring moment of a planing craft operating at planing speeds. A series of tow tests using a prismatic hull with a constant deadrise of 20 measured the lift force and righting moment at various angles of heel and at various model velocities. The model was completely constrained in surge, sway, heave, roll, pitch, and yaw. The underwater volume is determined from the known hull configuration and the underwater photography of the keel and chine wetted lengths. The results presented include the total lift and righting moment with the hydrostatic and hydrodynamic contributions for various model speeds at two model displacements.

Hydrodynamics of High-Speed Planing Craft: Savitsky Method and 2D+t Approach

2021 ◽  
Author(s):  
M. Javad Javaherian ◽  
Richard Royce ◽  
Raju Datla ◽  
Christine M. Gilbert
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Hydrodynamic Force ◽  
Prediction Method ◽  
Water Entry ◽  
Planing Craft ◽  
Towing Tank ◽  
Entry Model ◽  
Calm Water

The progressive interest in high-speed planing craft has made it crucial to conduct more accurate assessments of the behavior of these vessels in motion. In this paper, a 2D+t approach is employed to predict the resistance, trim and wetted length of a prismatic planing craft cruising in calm water. Although this approach is based on original Zarnick 2D+t model, the hydrodynamic force is estimated using experimental wedge drop experiments in conjunction with the Logvinovich wedge water entry model. The analysis is repeated employing Savitsky prediction method and results are compared with that of towing tank measurements of Naples series. The comparison shows that the Savitsky prediction results match very well with the experimental data. The 2D+t approach also shows reasonable outcomes for the trim and wetted length. However, this approach slightly underestimates the resistance of the craft at very low Froude numbers.

Numerical Simulation of Dynamic Response of Planing Craft Sailing in Calm Water

2014 ◽  
Vol 590 ◽  
pp. 37-41
Author(s):  
Yu Min Su ◽  
Yun Hui Li ◽  
Hai Long Shen
Keyword(s):  
Numerical Simulation ◽  
Empirical Formula ◽  
High Speed ◽  
Evaluation Method ◽  
Simulation Method ◽  
Experimental Results ◽  
Planing Craft ◽  
Calm Water ◽  
Performance Evaluation Method ◽  
Good Agreement

In order to forecast the sailing response of planing craft at high speed rapidly and accurately, CFD code Fine/Marine solver was used to calculate the resistance and sailing attitude of a high-speed planing craft, then the numerical results were compared with experimental results and empirical formula results. The results showed that resistance error calculated by Fine/Marine was between 5% and 10%, trim and heave results were in good agreement with experimental results, and had greater accuracy compared with the empirical formula results. The feasibility of this numerical simulation method was validated and this method provided an effect performance evaluation method for new designing planing crafts.

Empirical Methods for Predicting Lift and Heel Moment for a Heeled Planing Hull

2014 ◽  
Vol 30 (04) ◽  
pp. 175-183
Author(s):  
Carolyn Q. Judge
Keyword(s):  
High Speed ◽  
Experimental Program ◽  
Naval Academy ◽  
Forward Speed ◽  
Empirical Methods ◽  
Empirical Relationships ◽  
Planing Craft ◽  
Underwater Photography ◽  
Calm Water ◽  
Transverse Stability

Even in calm water, high-speed vessels can display unstable behaviors such as chine walking, sudden large heel, and porpoising. Large heel angle can result in the loss of transverse stability at high forward speed. When a planing craft begins to plane, the hydrodynamic lift forces raise the hull out of the water, reducing the underwater geometry. An experimental program at the U.S. Naval Academy has been designed to investigate the transverse stability of planing hulls. An experimental mechanism to force a planing hull model in heave and roll motion was designed and built. The first model tested was a wooden prismatic planing hull model with a constant deadrise of 20, a beam of 1.48 ft (0.45 m), and a total length of 5 ft (1.52 m). The model was held at various heel and running draft positions while fixed in pitch, yaw, and sway. The tests were done at two model speeds, for one model displacement, five fixed heel angles, and five fixed running heave positions. The lift and sway forces, along with the heel moment, were measured and underwater photography was taken of the wetted surface. This article presents a set of equations based on empirical relationships for calculating the lift and heel moment for a prismatic planing hull at nonzero heel angles.

A Case Study of Dynamic Instability in a Planing Hull

1987 ◽  
Vol 24 (02) ◽  
pp. 143-163
Author(s):  
Louis Codega ◽  
James Lewis
Keyword(s):  
High Speed ◽  
Dynamic Instability ◽  
Test Procedure ◽  
Large Angle ◽  
Model Tests ◽  
Full Scale ◽  
Planing Craft ◽  
Normal Operating ◽  
Full Scale Tests

Soon after introduction into service, a class of high-speed planing boats began to exhibit a dynamic instability that manifested itself in the craft trimming by the bow, rolling to a large angle of heel to port, and broaching violently to starboard, all within five seconds. This behavior, which occurred within the craft's normal operating envelope, could not be attributed to operator causes and resulted in unacceptable operating restrictions being placed on the craft. After a number of unsuccessful attempts to remedy the problem, an investigation to research possible causes was undertaken. Concurrently, a test boat was instrumented to quantify its behavior and, most importantly, to record the hydrodynamic bottom pressures acting while this phenomenon occurs. The craft is described and initial attempts at solving the problem are outlined. The results of research on this type of phenomena in both planing craft and flying boats are presented. The instrumentation system, complex for this size craft, is detailed and the test procedure described. The results of the full-scale tests are given, along with qualitative comparisons with other craft that display a similar problem and model tests that would indicate the possibility of such instabilities. The cause of the instability is described and recommendations are made to avoid similar problems in future craft.

Hydrodynamic Performance and Appendage Considerations of Wave-Piercing Planing Craft Overlapping Waves and Porpoising

2019 ◽  
Author(s):  
Sang-Won Kim ◽  
Sang-Eui Lee ◽  
Gyoung-Woo Lee ◽  
Kwang-Cheol Seo ◽  
Nobuyuki Oshima
Keyword(s):  
Numerical Simulation ◽  
Pressure Distribution ◽  
High Speed ◽  
Numerical Study ◽  
Hydrodynamic Performance ◽  
Moving Mesh ◽  
Navier Stokes ◽  
Hull Form ◽  
Wave Condition ◽  
Planing Craft

Abstract This work addresses the numerical study of wave-piercing planing hull and related hydrodynamic performance as the appendages. From the half century ago, the interest in high-speed planing crafts has been advanced toward maintaining performance stably. The main reasons to make it hard are instability motion occurring from porpoising and wave condition. Porpoising is mainly due to overlap the heaving and pitching motion with certain period, which is caused by instable pressure distribution and changing longitudinal location of center of gravity. In addition, in wave condition, encountering wave disturbs going into planing mode. This paper presents numerical results of wave-piercing planing hull in porpoising and wave condition. Numerical simulation is conducted via Reynolds Averaged Navier-stokes (RANS) with moving mesh techniques (overset grid), performed at different wave condition. The results for the behaviors of wave-piercing hull form are practically presented and investigated in this study. The understanding of these phenomena is important for design of appendages of wave-piercing hull-form.

Experimental and numerical analyses of wedge effects on the rooster tail and porpoising phenomenon of a high-speed planing craft in calm water

2019 ◽  
Vol 233 (13) ◽  
pp. 4637-4652 ◽  
Author(s):  
Sayyed Mahdi Sajedi ◽  
Parviz Ghadimi ◽  
Mohammad Sheikholeslami ◽  
Mohammad A Ghassemi
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Scale Model ◽  
Test Cases ◽  
Planing Craft ◽  
Calm Water ◽  
Space Discretization ◽  
Good Agreement

This paper presents experimental and numerical investigation of stability and rooster tail of a mono-hull high-speed planing craft with a constant deadrise angle. Initially, a one-fifth scale model was tested in a towing tank, which showed porpoising phenomenon at 8 m/s (equal to the speed of sailing). Subsequently, two wedges of 5 and 10 mm heights, based on the boundary layer calculations, were mounted on the aft section of the planing hull. These wedges were shown to increase the lift at the aft section. These experiments were carried out at different speeds up to 10 m/s in calm water. The experimental results indicated that the installed wedges reduced the trim, drag, and the elapsed time for reaching the hump peak, and also eliminated the porpoising condition. All these test cases were also numerically simulated using Star CCM+ software. The free surface was modeled using the volume of fluid scheme in three-dimensional space. The examined planing craft had two degrees of freedom, and overset mesh technique was used for space discretization. The obtained numerical results were compared with experimental data and good agreement was displayed in the presented comparisons. Ultimately, the effect of the wedge on the rooster tail behind the planing craft was studied. The results of this investigation showed that by decreasing the trim at a constant speed, the height of the generated wake profile (rooster tail) behind the craft decreases, albeit its length increases.

scholarly journals Numerical Study of Hydrodynamics of Heavily Loaded Hard-Chine Hulls in Calm Water

2021 ◽  
Vol 9 (2) ◽  
pp. 184
Author(s):  
Miles P. Wheeler ◽  
Konstantin I. Matveev ◽  
Tao Xing
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
The Other ◽  
Hydrodynamic Performance ◽  
Pressure Distributions ◽  
Wave Patterns ◽  
Speed Range ◽  
Calm Water ◽  
Program Star ◽  
Displacement Regime

Hard-chine boats are usually intended for high-speed regimes where they operate in the planing mode. These boats are often designed to be relatively light, but there are special applications that may occasionally require fast boats to be heavily loaded. In this study, steady-state hydrodynamic performance of nominal-weight and overloaded hard-chine hulls in calm water is investigated with computational fluid dynamics solver program STAR-CCM+. The resistance and attitude values of a constant-deadrise reference hull and its modifications with more pronounced bows of concave and convex shapes are obtained from numerical simulations. On average, 40% heavier hulls showed about 30% larger drag over the speed range from the displacement to planing modes. Among the studied configurations, the hull with a concave bow is found to have 5–12% lower resistance than the other hulls in the semi-displacement regime and heavy loadings and 2–10% lower drag in the displacement regime and nominal loading, while this hull is also capable of achieving fast planing speeds at the nominal weight with typical available thrust. The near-hull wave patterns and hull pressure distributions for selected conditions are presented and discussed as well.

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