An Overview of Stepped Hull Performance Evaluation: Sea Trial Data vs Full-Scale CFD Simulation

It is well known that the dynamic of the stepped hull in real scale is rather complex and it’s not easy to predict that using empirical or mathematical approaches, and by the numerical and experimental way as well. Moreover, there is a huge lack in the literature of data related to sea trials of the stepped hull. Furthermore, the reliability of full-scale CFD simulations is not widely proven and validated especially for high speed and planing hull. For these several reasons, in this paper, the authors are focused on the comparison of the results carried out from model experimental tests performed in the model basin, full-scale CFD simulations, and sea trial tests. The performed simulations in full-scale have been compared to the extrapolated experimental tests and the sea-trial results. Moreover, the dynamic trim angle and the dynamic wetted surface have been taken into account to assess the reliability of the full-scale simulation performed. The stepped hull considered is a Mito 31 outboard Rigid Inflatable Boat (RIB) built by MV Marine Srl Company.

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Full Scale Measurements and Flow Analysis on a High Speed Rescue/Patrol Boat

10.5957/fast-2015-042 ◽

2015 ◽

Author(s):

Hans Jørgen Mørch ◽

Thomas Larsen ◽

Erik Mostert ◽

Karl Marius Norschau ◽

Gunnar Semb

Keyword(s):

High Speed ◽

Cfd Simulation ◽

Flow Analysis ◽

Full Scale ◽

Limiting Factor ◽

Safe Operation ◽

Cfd Simulations ◽

Measurement Results ◽

Calm Water ◽

Operational Envelope

Through use of state of the art tools for flow analysis the aims to establish a methodology to determine the performance of a high speed planing craft both in calm water and in waves. Verification against full scale measurements is conducted. The ability to maintain speed in waves is of great interest -both with respect to added resistance and with respect to safe operation and loads on the crew from accelerations. Full scale measurements and CFD (Computational Fluid Dynamics) were conducted on a Norsafe Magnum 850fast patrol boat. The measurements have been conducted during a boat challenge along the Iberian coast. The challenge was run in advance of the HSBO (High Speed Boat Forum) which was held in Lisbon, Portugal, May2015.CFD simulations at similar conditions to the measurements are used for validation. It is further shown how CFD can be used to expand operational envelopes beyond the point where full scale measurements are applicable. This is especially relevant for the acceleration loads on the crew which is often the limiting factor of small HSC (High Speed Crafts). Pressure loads are extracted from the CFD and are evaluated against the current standards for life boats. Various criteria are discussed and the most relevant are analyzed for the measurement results and the CFD simulation. An operational envelope where the different criteria are combined is suggested.

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A comparative review of the resistance of a 37,000 dwt Chemical Tanker based on experimental tests and calculations

Technium: Romanian Journal of Applied Sciences and Technology ◽

10.47577/technium.v1i.32 ◽

2020 ◽

Vol 1 ◽

pp. 59-66

Author(s):

Liviu Crudu ◽

Radu Bosoancă ◽

Dan Obreja

Keyword(s):

Energy Efficiency ◽

Experimental Tests ◽

Full Scale ◽

The Other ◽

Towing Tank ◽

Ship Resistance ◽

Comparative Review ◽

Cfd Applications ◽

Energy Efficiency Design Index ◽

Comparison Of The Results

The evaluation of ship resistance is of paramount importance having a decisive impact on the economic performances and efficiency depending on mission. If new IMO requirements through the Energy Efficiency Design Index (EEDI) are taken into account the necessity to have more and more accurate tools capable to consider the influences of different parameters became mandatory. The availability of towing tank facilities and the full scale trials are the practical means in order to be able to confirm the accuracy of theoretical formulations and to define the limits of CFD applications. Based on the results of the towing tank tests, a direct comparison with the results provided by classical methods and CFD computations can be systematically can be performed. On the other hand, the influences of the modifications operated on the fore part of the ship aretheoretically evaluated and compared with the towing tank results. Consequently, the paper is focused on the comparison of the results evaluated using different tools which have been carried out for a Chemical Tanker built by Constanta Shipyard Romania.

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CFD and Experimental Analysis of Centrifugal Fans With Forward Curved Blades Used in Electric Motors

Volume 1: Aircraft Engine; Fans and Blowers; Marine; Honors and Awards ◽

10.1115/gt2019-91688 ◽

2019 ◽

Author(s):

S. S. Borges

Keyword(s):

Cfd Simulation ◽

Experimental Tests ◽

Performance Comparison ◽

Centrifugal Fan ◽

Electric Motors ◽

Cfd Simulations ◽

Interface Models ◽

Ansys Cfx ◽

Centrifugal Fans ◽

Computational Fluid Dynamics Cfd

Abstract This work presents an analysis of the aerodynamic performance of a centrifugal fan with forward curved blades (Sirocco) applied to electric motors. In this analysis were carried out computational fluid dynamics (CFD) simulations and experimental tests for comparison of results. The focus of this analysis is the performance comparison among three different models of general connection interface that are required for the connection between the grids of the rotating and stationary domains of CFD simulation, considering the method adopted by the Ansys CFX, software used as computational tool. Thereby, Frozen Rotor, Stage, and Transient Rotor-Stator were the interface models evaluated. For comparison reference, the experimental data were used to evaluate the performance of each interface models for overall operating range of the fan.

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Experimental Verification of CFD Simulation When Evaluating the Operative Temperature and Mean Radiation Temperature for Radiator Heating and Floor Heating

Processes ◽

10.3390/pr9061041 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1041

Author(s):

Pavol Mičko ◽

Andrej Kapjor ◽

Michal Holubčík ◽

Dávid Hečko

Keyword(s):

Cfd Simulation ◽

Heating System ◽

Radiation Temperature ◽

Cfd Simulations ◽

Thermal Discomfort ◽

Heating Systems ◽

Comparison Of The Results ◽

Positive Effect ◽

Suitable Environment

The assessment of heating systems is not only interested in the efficiency of the heating system itself, but also in the quality of the environment that the heating system creates. The quality of the environment and the heat-humidity microclimate is closely related to thermal comfort. A suitable environment has a positive effect, for example, on the efficiency of work at the workplace. The range of temperatures, humidity and operating temperatures in workplaces is often also legally prescribed in such a way that there is no thermal discomfort for users in the heated space. In terms of savings, it is therefore best to use heating systems that can create a comfortable environment with the lowest possible energy costs. During their development, variations are possible with temperature gradients, the size of the heat exchange area, or the ratio of the radiant and convective components of heat transfer. When developing such systems, it is appropriate to consider CFD simulations. The comparison of the results of CFD simulation and experimental measurement is also in the following article, where the comparison of the operating temperature and the mean radiation temperature of two different heating systems in the model office is monitored.

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Design of a High Speed Internal Gear Pump to Increase the Power Density of Electro Hydraulic Actuators (EHA) in Mobile Applications

Volume 7: Fluids Engineering ◽

10.1115/imece2019-10351 ◽

2019 ◽

Author(s):

Tobias Pietrzyk ◽

David Roth ◽

Georg Jacobs ◽

Schmitz Katharina

Keyword(s):

High Speed ◽

Cfd Simulation ◽

Mechanical Efficiency ◽

Gear Pump ◽

Suction Pressure ◽

Shaft Seal ◽

Test Rig ◽

Cfd Simulations ◽

Internal Gear ◽

High Suction

Abstract Increasing the rotational speed of the internal gear pump entails addressing topics such as cavitation, overheating and filling problems of the tooth spaces. Besides the development of a tooth geometry and flow optimization, using CFD simulation is necessary. This paper discusses the design of the newly developed high speed internal gear pump. This includes a detailed description of the different parts as well as the dimensioning of the pump by using CFD simulations. The geometry of the pressure build-up groove has a significant effect of pressure build up inside the pump. Therefore, three different geometries are investigated. The calculation of the journal bearings for the internal gear as well as for the driving shaft is shown. To avoid cavitation problems, the suction pressure of the pump will be increased up to 25 bar. This paper will show the technical arrangements to reach this high suction pressure level whilst still using a radial shaft seal ring. In order to determine the efficiency of the newly developed high speed pump, a test rig was built up. The test rig allows the measurement of the volumetric efficiency as well as the hydraulic-mechanical efficiency at different operation points up to 10 000 rpm and 250 bar.

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Motion Modeling and Simulation of High-Speed Unmanned Surface Vehicle

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.44-47.1588 ◽

2010 ◽

Vol 44-47 ◽

pp. 1588-1592 ◽

Cited By ~ 1

Author(s):

Jin Yue ◽

Guang Ren ◽

Xiao Liang ◽

Xiao Wei Qi ◽

Geng Tian Li

Keyword(s):

High Speed ◽

Software Tool ◽

Trial Data ◽

Motion Model ◽

Motion Modeling ◽

Unmanned Surface Vehicle ◽

Sea Trial ◽

Proposed Model ◽

Motion Characteristic ◽

Ocean Environment

According to the motion characteristic and the hydrodynamics of high-speed deep-V planings, forces and moments acted on a deep-V planing propelled by a contra-rotating propeller were analyzed, and on the basis of MMG modeling method, a real-time 6DOF mathematical motion model for the high-speed unmanned surface vehicle(USV) was built and the performance was simulated using the Matlab/Simulink software tool. Compared with the actual sea trial data, the results show that the proposed model can better reflect and simulate the maneuverability of the USV under ocean environment.

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Optimal trim control of a high-speed craft by trim tabs/interceptors Part I: Pitch and surge coupled dynamic modelling using sea trial data

Ocean Engineering ◽

10.1016/j.oceaneng.2016.12.007 ◽

2017 ◽

Vol 130 ◽

pp. 300-309 ◽

Cited By ~ 8

Author(s):

Melek Ertogan ◽

Philip A. Wilson ◽

Gokhan Tansel Tayyar ◽

Seniz Ertugrul

Keyword(s):

High Speed ◽

Dynamic Modelling ◽

Trial Data ◽

Sea Trial

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Time Domain Simulation Model for Research Vessel Gunnerus

Volume 7: Ocean Engineering ◽

10.1115/omae2015-41786 ◽

2015 ◽

Cited By ~ 2

Author(s):

Vahid Hassani ◽

Andrew Ross ◽

Ørjan Selvik ◽

Dariusz Fathi ◽

Florian Sprenger ◽

...

Keyword(s):

Simulation Model ◽

Time Domain ◽

Trial Data ◽

Full Scale ◽

Dynamic Equations ◽

Scale Model ◽

Research Vessel ◽

Oil Exploration ◽

Time Domain Simulation ◽

Sea Trial

A research vessel (RV) plays an important role in many fields such as oceanography, fisheries and polar research, hydrographic surveys, and oil exploration. It also has a unique function in maritime research and developments. Full-scale sea trials that require vessels, are usually extremely expensive; however, research vessels are more available than other types of ship. This paper presents the results of a time-domain simulation model of R/V Gunnerus, the research vessel of the Norwegian University of Science and Technology (NTNU), using MARINTEK’s vessel simulator (VeSim). VeSim is a time-domain simulator which solves dynamic equations of vessel motions and takes care of seakeeping and manoeuvring problems simultaneously. In addition to a set of captive and PMM tests on a scale model of Gunnerus, full-scale sea trials are carried out in both calm and harsh weather and the proposed simulation model is validated against sea trial data.

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Scale Effects on Ship Maneuverability Using RANS

Volume 2: CFD and FSI ◽

10.1115/omae2018-77191 ◽

2018 ◽

Author(s):

Motoki Araki

Keyword(s):

Cfd Simulation ◽

Scale Effects ◽

Full Scale ◽

Navier Stokes ◽

Cfd Simulations ◽

Ship Maneuvering ◽

Ship Maneuverability ◽

Computational Fluid Dynamics Cfd ◽

Rudder Angle ◽

Maneuvering Simulations

Predicting ship maneuverability is one of the important topics in ship engineering. However because of the huge difference between model and full scale Reynolds number (Re), it is almost impossible to predict full scale ship maneuverability using conventional methods such as model test. On the other hands, with the developments of computational technologies and computational fluid dynamics (CFD) techniques, CFD simulations are widely applied on ship maneuvering problems (e.g. Stern et al., 2011). Moreover some of the researchers start the CFD simulation with full scale Re especially on propulsion problems (e.g. Tezdogan et al., 2015) which showing reasonable results. Therefore, in this paper, captive maneuvering simulations (rudder angle test) in model/full scale Re on KVLCC2 are carried out using Reynolds-averaged Navier–Stokes (RANS) solver NAGISA (Ohashi et al., 2014) with the overset gird method UP_GRID (Kodama et al., 2012). And the results between model and full scale simulations are compared in maneuvering coefficients and flow field to reveal the scale effect on ship maneuverability.

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