Experimental Technology Of Resistance Performance In Actual Sea And Numerical Simulation Of 25m-ship Model

In recent years,more and more attention has been paid to the research on the adaptability of various types of ships in the ocean and obtaining accurate testing results for ship performance forecast becomes strong.The methods of traditional ship performance forecast are obtained by numerical simulation and physical model test.Due to the model scale effect,the principal dimensions and performance of experimental pool,we often can not get the performance characteristics of sailing ship truly,even appearing the wrong phenomenon.Scantling sea trials is the most real and reliable test method to reflect the hydrodynamic performance of ships.However,due to the limitations of difficult implementation conditions,long manufacturing cycle and expensive test costs,it can not be widely used in scientific research.The test technology of large scale ship in real sea has advantages of both model test in towing tank and sea trials test,which can reduce the scale effect of ship,and the test is carried out in real environment,which greatly improves measurement and evaluation on the accuracy and reliability of ships comprehensive performance.This paper aims to demonstrate the feasibility of 25m-ship resistance performance,build the comprehensive test system of 25m-ship in real sea,establish the comprehensive testing methods in real sea.Based on these aspects,this article mainly carries out research work from the following three parts:(1)first,the theoretical basis and technical requirements of ship resistance test are introduced.In the aspect of ship theoretical basis,the classification,characteristics and generation mechanism of ship resistance are mainly described.The common conversion methods of resistance,such as Froude conversion and Hughes conversion from characteristics and mechanism,are analyzed.In the aspect of resistance test,it mainly includes the design principle of experiment ship model,the law and principle of ship experiment.(2)then,the design ot resistance test scheme in real sea for 25m-ship model is described in detail.This paper introduces four parts,including statistics of sea condition information and selection test area,design and manufacture of 25m-model,equipment and system platform of sea trials testing,resistance test plan and data analysis.1)statistics of sea condition information and selection test area.including getting the information about monsoon cyclones,wave,tidal and choosing the most suitable place for 25m-ship model to do resistance experiment.2)The design and manufacture of 25m-model,including the precision control of ship model line,design of hull skeleton,transverse bulkhead and hatch to meet the requirements of structural strength,platform arrangement;3)The equipment and system platform of sea trials testing,including instrument and equipment precision and range control,equipment installation and debugging,general arrangement of instrument and equipment,establishment of sea test system platform and itemized system integration;4)The resistance test plan of 25m-ship in real sea,including expert demonstration of resistance test plan,division of labor and dispatch of resistance test,detailed description of resistance test process,and safety service facilities during sea test.(3)finally,using STAR-CCM+ soft to research hydrodynamic performance about 25m-ship model,by controlling the number of grid,selection of turbulence model,setting up the physical parameters,at the same time the VOF method is adopted to capture free surface wave change and field information.Combining with 25m-ship data in real sea and numerical simulation,analysis ship resistance performance accurately and efficiently.Based on the basic theory of ship resistance test,the design of the resistance test scheme,the sea trial flow and data analysis,and the numerical simulation calculation of 25m-ship resistance,this paper elaborates and studies the large-scale ship resistance test technology in the sea area,and establishes the test method for ship resistance in real environment.In addition,the 25m-ship resistance test was carried out in Qingdao sea area,showing the feasibility of sea testing scheme and the reliability of test system.By analyzing test data of 25m-ship model and numerical simulation,the development prospect and far-reaching significance of large-scale ship model test in real environment are described.