Wave Interference Prediction of a Trimaran Using Form Factor

2020 ◽  
Author(s):  
Suleyman Duman ◽  
Ali Dogrul ◽  
Burak Yildiz ◽  
Raju Datla
Keyword(s):  
Form Factor ◽  
High Speed ◽  
Interference Phenomenon ◽  
Wave Interference ◽  
Calm Water ◽  
Surface Combatant ◽  
And Performance ◽  
Hull Forms ◽  
Cfd Method ◽  
Turbulent Flow Conditions

The increasing demands in high-speed transportation have brought the multi-hull forms into the forefront. Many applications have already been realized in civil transportation and naval purposes. The design features and performance characteristics of these vessels differ from mono-hull due to the wave interference phenomenon. Nowadays, evaluation of ship hydrodynamics with CFD has become very popular and successful results have been achieved. Based on this, it is aimed to contribute to the prediction of wave interference effects of a trimaran surface combatant, advancing in deep, unbounded and calm water, by applying the CFD method. A trimaran model with a scale of 1/125 was chosen for the numerical investigation. Primarily, a V&V study was conducted by using proper techniques. Then, the form factor of the trimaran was calculated with two different methods: Prohaska and double-body. The hydrodynamic analyses were performed under incompressible, viscous and fully turbulent flow conditions. Computational results were compared in terms of resistance components and interference factors. The form factor prediction methods were discussed regarding wave interference.

Pure Yaw Simulations of Fast Delft Catamaran 372 in Deep Water

2020 ◽  
Author(s):  
Suleyman Duman ◽  
Sakir Bal
Keyword(s):  
Deep Water ◽  
High Speed ◽  
Point Of View ◽  
Hydrodynamic Performance ◽  
Marine Vehicles ◽  
Wave Interference ◽  
Force Moment ◽  
Unsteady Rans ◽  
Cfd Method ◽  
Turbulent Flow Conditions

Fast marine vehicles have become more important than ever before due to increasing need and population. In maritime sector, special ship types such as catamaran and trimaran have already been designed and/or built to the civil and naval areas of use. The hydrodynamic performance of these vessels is an interesting problem for naval architects due to the wave interference between the hulls. From this point of view, a generic high-speed catamaran hull form (Delft catamaran 372 or DC372) has been chosen for the numerical prediction of manoeuvring coefficients. To achieve this, the pure yaw captive manoeuvre simulations of the DC372 have been performed in deep water conditions at several oscillating frequencies by using CFD method. The unsteady RANS equations have been solved under incompressible, viscous and fully turbulent flow conditions. The uncertainty in the computations has been determined using proper techniques. Manoeuvring coefficients have been calculated by processing time dependent force/moment signals obtained numerically with the help of Fourier analysis. Due to the accurate grid structure used here, numerical ventilation has been prevented and wave deformations have been captured well.

Concept Exploration of a Surface Effect Patrol Combatant Using a Multiobjective Synthesis Model

2021 ◽  
Author(s):  
Harry P. Crosby ◽  
Katherine E. Zalegowski ◽  
Raphael Christian C. Batto
Keyword(s):  
High Speed ◽  
Surface Effect ◽  
Optimization Techniques ◽  
Concept Design ◽  
Highly Nonlinear ◽  
Concept Exploration ◽  
3D Geometry ◽  
Objective Space ◽  
Surface Combatant ◽  
And Performance

This paper demonstrates a concept design methodology for naval SESs that is adapted from modern surface combatant optimization techniques. Similar to current methods, a synthesis model is constructed that uses a variety of discrete and continuous input values to calculate ship characteristics and performance data. The model outputs are generated using a combination of first-principles and exact 3D geometry along with parametrics aggregated from conventional monohulls and SES historical data. A specifically formulated multiobjective genetic algorithm is integrated with the model. The algorithm explores the highly nonlinear and non-convex SES objective space to identify non-dominated design variants. The synthesis model and the associated design space for a patrol boat with a novel SES hullform is detailed. Tradeoffs are evaluated in objective criteria of cost and performance in high-speed littoral operations that include surveillance, reconnaissance, and surface warfare.

Comparative Investigation of an Automated Oceanic Wave Surface Glider Robot Influence on Resistance Prediction Using CFD Method

2015 ◽  
Vol 710 ◽  
pp. 91-97
Author(s):  
Aladdin Elhadad ◽  
Wen Yang Duan ◽  
Rui Deng
Keyword(s):  
High Speed ◽  
Water Resistance ◽  
Comparative Investigation ◽  
Numerical Predictions ◽  
Calm Water ◽  
Oceanic Wave ◽  
Computational Fluid Dynamics Cfd ◽  
Wave Glider ◽  
Cfd Method ◽  
Solution Parameters

Thewave glideris composed of two parts: the float is roughly the size and shape of a surfboard that contains all the instrumentation needed for scientific experiments; the sub has wings and hangs 6 meters below on an umbilical tether. This difference allows wave energy to be harvested to produce forward thrust. According to the lake of design information and data for thewave glider, the main aim of the study is usingcomputational fluid dynamics (CFD)to present a method to predict calm water resistance for the floating part of thewave glider(the hull).Wigley parabolic hulland high speed round bilge form (NPL)have been investigated in order to estimate the hydrodynamic performances of the hull usingCFDsoftware fluent.Wave glideris designed with slender hull shapes in order to decrease the wave making resistance of the ship.In this paper a method is evaluated by comparing the numerical predictions forwigleyandNPLforms (2m) using the same mesh generation method under the same conditions to design the hull. Calculations fortotal calm water resistanceare carried out using three different mesh sizes for Froude numbers in the range of 0.10 to 0.40 and compared for accuracy of the solution parameters. The close agreement between the numerical predictions shows the importance ofCFDapplications in estimating the hydrodynamics performance to design the floating hull and the numerical method is useful in glider design. This means that the method discussed in this paper can be used for the resistance calculation of some hulls like the float of the glider.

scholarly journals Low-Cost 400 Gbps DR4 Silicon Photonics Transmitter for Short-Reach Datacenter Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1941
Author(s):  
Haike Zhu ◽  
Sean Anderson ◽  
Nick Karfelt ◽  
Lingjun Jiang ◽  
Yunchu Li ◽  
...  
Keyword(s):  
Form Factor ◽  
Silicon Photonics ◽  
High Speed ◽  
Low Cost ◽  
Optical Components ◽  
Test Board ◽  
Silicon Photonic ◽  
Transceiver Module ◽  
Photonic Circuit ◽  
And Performance

Targeting high-speed, low-cost, short-reach intra-datacenter connections, we designed and tested an integrated silicon photonic circuit as a transmitter engine. This engine can be packaged into an optical transceiver module which meets the QSFP-DD Form Factor, together with other electrical/optical components. We first present the design and performance of a high-speed silicon modulator, which had a 3-dB EO bandwidth of >40 GHz and an ER of >5 dB. We then incorporated the engine onto a test board and injected a 53.125 Gbaud PAM4 signal. Clear eye patterns were observed at the receiver with TDECQ ~3 dB for all four lanes.

An Analysis of Rigid Sidewall Surface Effect Craft for High-Speed Personnel Transportation

1970 ◽  
Vol 7 (01) ◽  
pp. 55-68
Author(s):  
Eugene R. Miller
Keyword(s):  
High Speed ◽  
Surface Effect ◽  
Transportation Cost ◽  
Total Power ◽  
Design Parameters ◽  
Economic Criterion ◽  
Calm Water ◽  
And Performance ◽  
Commercial Applications ◽  
Sidewall Surface

A number of commercial applications have been proposed for rigid sidewall surface effect craft. The transport of crews to offshore operations is an application which is well-suited to the immediate use of moderately sized craft of this type. Because the crews are paid while they are in transit, high speeds are required to minimize the total transportation costs. The characteristics and performance of rigid sidewall surface effect craft suitable for crew transport operations are developed. The major design parameters studied include pay-load, total power, and machinery type. Performance estimates are made for operations in both calm water and waves. An economic model is developed to simulate crewboat operations. Cost estimates are based on current technology and price levels. The total unit transportation cost is used as the economic criterion in the determination of the relative merit of various craft. For the purpose of comparison the characteristics and costs of planing hull crewboats for the same mission are developed. It is concluded that rigid sidewall surface effect craft have the potential of being economically superior to planing boats for crew transport operations.

Experimental Analysis on Flow around Fin Assisted Semi SWATH

2015 ◽  
Vol 74 (5) ◽  
Author(s):  
Arifah Ali ◽  
Adi Maimun ◽  
Yasser M. Ahmed ◽  
Rahimuddin Rahimuddin ◽  
Mohamad Pauzi A. Ghani
Keyword(s):  
Froude Number ◽  
High Speed ◽  
Water Resistance ◽  
Wave Pattern ◽  
Resistance Test ◽  
Hull Form ◽  
Wave Interference ◽  
Calm Water ◽  
Water Test ◽  
Zero Degree

Demand on High Speed Craft (HSC) is increasing due to development of inland transportation. Therefore, many analysis have been conducted to evaluate performance of this modern ship. One of the important analysis is calm water resistance test. Resistance component of the hull and wave pattern around the hull are obtained from the calm water test. These criteria are important in analyzing flow around hull, especially on wave interference between the hulls. In this paper, flow around hull has been studied for one model of Semi SWATH hull form with fin stabilizers installation by performing calm water resistance test in deep water. The fore fin angle is fixed to zero degree while the aft fin angle is varied to 0, 5 and 15 degree. The effects of fin angle to resistance criteria and flow around hull are investigated. Wave height has been recorded using longitudinal wave probe during resistance test. For each configuration, the investigation is conducted with range of Length Froude Number from 0.34 to 0.69. From the analysis, it is found that flow around the hull of Semi SWATH is affected by fin angle and the effect is various depend on the Froude number.

Design and Application of Modern High-Speed Catamarans

1972 ◽  
Vol 9 (03) ◽  
pp. 345-357
Author(s):  
Edward D. Fry ◽  
Timothy Graul
Keyword(s):  
Test Data ◽  
Model Test ◽  
High Speed ◽  
Structural Strength ◽  
Trade Off ◽  
Océanographic Survey ◽  
Parametric Studies ◽  
And Performance ◽  
Hull Forms ◽  
Design And Application

Modern power catamarans of planing type are investigated. Data are presented about small high-speed catamarans (40 ft< LOA < 100 ft) which have seen oceanographic, survey, excursion and fishing service. A table of characteristics of recently constructed catamarans is included. Some results and observations based on extensive parametric studies of asymmetrical and symmetrical planing catamaran hulls are included. Curves of R/D versus speed for various displacements, hull spacings and hull forms are presented. An attempt is made to relate size, weight, power and performance by comparing known performance to model test data. Considerations involved in the design of catamarans such as structural strength, powering, stability, handling peculiarities and weight criticality are discussed. Methods of predicting weight, cost and considerations for trade-off analyses are presented.

CFD Simulation of Resistance of Highspeed Trimaran Hullforms

2015 ◽  
Author(s):  
Changhwan Son ◽  
Prasanta K. Sahoo ◽  
Vaibhav Aribenchi ◽  
Srikanth Asapana
Keyword(s):  
High Speed ◽  
Cfd Simulation ◽  
Accurate Determination ◽  
Cfd Analysis ◽  
Test Results ◽  
Ansys Fluent ◽  
Speed Range ◽  
Calm Water ◽  
Hull Forms

This paper attempts to carry out a CFD analysis on total resistance for trimaran hull forms based on established NPL systematic series which are high-speed round bilge hull forms. The resistance of high-speed trimaran hull forms have been determined using ANSYS FLUENT, a CFD software package. A systematic series of round bilge demi-hulls were generated, and their resistance in calm water were determined by using ANSYS FLUENT to briefly examine nature and degree of reliability of ANSYS FLUENT. The primary aim of this investigation is to determine resistance characteristics of slender round bilge trimaran hull forms in the high-speed range corresponding to Froude numbers up to 1.0. Model test results obtained from the paper Molland et al (1994) have been used to verify the efficacy of the CFD analysis. The results obtained from CFD have shown considerable promise and further analysis need to be carried out for accurate determination of resistance in trimaran configuration.

A Simple Method for Predicting the Maximum Squat of a High-Speed Displacement Ship

2006 ◽  
Vol 43 (03) ◽  
pp. 146-151
Author(s):  
Tim Gourlay
Keyword(s):  
Satisfactory Agreement ◽  
Model Test ◽  
High Speed ◽  
Simple Formula ◽  
Test Results ◽  
Simple Method ◽  
Wide Range ◽  
Speed Range ◽  
Calm Water ◽  
Hull Forms

A simple formula is developed for predicting the maximum squat of a displacement ship as it passes through the transcritical speed range. This is given in terms of a maximum sinkage coefficient, which is almost constant across a wide range of hull forms. Satisfactory agreement is shown with model test results, and it is shown that large stern sinkages in the order of 3 to 6 meters are predicted for frigate and destroyer type hulls in shallow calm water.

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