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在系泊船模在波浪中的运动水工模型试验中,设计了一种试验测量仪器.该仪器可用于测量波浪作用下系泊船模的六自由度运动量.将6支拉绳式位移传感器固定在船模上方,每个传感器的拉绳均与下方的船模固定.船模晃动时会带动6根拉绳.根据6根拉绳长度变化和前一时刻船模的姿态,可以计算出船模运动的六自由度运动量.经波浪试验表明,该仪器可以很好地反应系泊船模的六自由度运动量,达到了预期的目的. 相似文献
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船模螺旋桨控制系统是为实船动力定位系统进行船模水池试验提供的动力驱动控制系统.为了满足测试环境、控制精度和响应速度的要求,船模螺旋桨控制系统采用西门子新推出的S7-1200 PLC控制器和V80伺服驱动器组合.通过测试和验证,该控制系统满足实船动力定位系统船模测试的控制要求,达到了预期目标,取得了良好的效果.此外,结合项目详细说明了如何应用S7-1200PLC进行控制系统的设计. 相似文献
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日本造船研究所船舶无压舱水革新设计 总被引:2,自引:0,他引:2
船舶压舱水不仅耗费大量海洋运输的能源、人力和物力,而且已经成为当今世界海洋的四大污染源之一。传统的压舱水处理剂技术无法从根本上解决船舶压舱水给海洋水资源带来的种种灾害。日本造船研究所进行了船舶无压舱水革新设计,并对革新型无压舱水油船船模和常规型有压舱水油船船模进行了系列测试。结果表明,无压舱水系统船舶设计理念和方案完全可行。 相似文献
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SSSRI作为ITTC的成员单位参加了ITTC阻力委员会发起的合作试验计划之工作,在SSSRI的2号水池中对系列60Cb=0.60的4条几何相似木质船模作了试验。4条船模的长分别是1.8、3.0、3.84及6.10米。对总阻力及波型测量其富氏数的范围是0.22—0.36,每条船模测了15个点。完整的尾流测量由于耗时太多,只对3.84米船模进行了测试,其富氏数范围为0.22—0.34,共计7个点,另外,对3.0米船模在Fn=0.22、0.26、0.30以及对6.10米船模在Fn-0.22、0.26时补充作了尾流测量,总阻力与两个阻力分量之间的符合程序是合理的,不同尺度船模的波型阻力之间出现了明显的不同,并对可能产生此情况的原因作了讨论。 相似文献
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利用数字图像来测定船模运动参数是一种成本低、精度高的方法。该系统利用数字图像技术实现了船模试验在自然光条件下的实时测量、实时数据处理和自动操纵控制。介绍了一套多CCD摄像机的船模自动测控系统,对电视图像变形修正、船模自动识别与跟踪等关键技术进行了详细的讨论。根据船模试验的特点提出了有别与一般目标识别跟踪的方法。 相似文献
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应用支持向量机对KVLCC2约束船模斜拖试验结果进行了分析,通过对有限样本数据的拟合,辨识了描述船体横向力和转首力矩的数学模型中的水动力导数。应用所获得的回归模型,对不同工况下的测试样本进行预报,预报结果和试验结果的比较验证了方法的有效性,可以用于指导约束船模试验。 相似文献
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以东海大桥海上风电场为研究背景,首先基于Biot固结理论求解了不同波况下多层非均质土体的位移、超孔压的分布,讨论了波浪荷载对海床运动的影响。而后基于土体位移计算结果,应用支座位移加载法与p-y曲线法相结合的方法,求解了运动海床作用下近海风机单桩基础的内力和变形,并将其结果与不考虑运动海床作用的结果进行了对比。对比结果显示:运动海床对桩身的变形影响显著,设计中有必要进行运动海床作用下的变形校核。 相似文献
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Computational predictions of ship-speed performance 总被引:1,自引:0,他引:1
Jung-Eun Choi Jung-Hun Kim Hong-Gi Lee Bong-Jun Choi Dong-Hyun Lee 《Journal of Marine Science and Technology》2009,14(3):322-333
This paper examines ship-speed performance based on acomputational method. The computations are carried out under identical
model conditions, i.e., resistance and self-propulsion tests, to predict the speed-power relationship. The self-propulsion
point is obtained from the self-propulsive computational results of two propeller rotative speeds. The speed-power relationship
in full scale is obtained through analyzing the computational results in model scale according to the model-ship performance
analysis method of ITTC’78. The object ship is a VLCC. The limiting streamlines and the distribution of the pressure coefficient
on the hull, the wake characteristics on the propeller plane, and the wave characteristics around a model ship are also investigated.
After completing the computations, a series of model tests are conducted to evaluate the accuracy of the predictions by comparing
the computational results with the experimental results. 相似文献
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Since cannon drum of agile shell-feeding system rotates frequently and intermittently, its motion must be steady. Outline of driving cam determines the motion of cannon drum, so it is necessary to select the proper outline of cam. Through analysis of parabolic outline and cycloid outline of the cams, the outline that combines the two curves is obtained. According to the demand of production, the value of the outline is revised, and then the method of fitting curve is used to get the expression of the angle of cam and the displacement of the driven part. Through analyzing the motion of the cannon drum, it is suggested that the angle of the cam is proportion to the displacement of the driven part. The cam with the specially derived outline can move steadily. 相似文献
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Hydrodynamic load and motion response are the first considerations in the structural design of a submerged floating tunnel (SFT). Currently, most of the relevant studies have been based on a two-dimensional model test with a fixed or fully free boundary condition, which inhibits a deep investigation of the hydrodynamic characteristics with an elastic constraint. As a result, a series of difficulties exist in the structural design and analysis of an SFT. In this study, an SFT model with a one-degree-of-freedom vertical elastically truncated boundary condition was established to investigate the motion response and hydrodynamic characteristics of the tube under the wave action. The effect of several typical hydrodynamic parameters, such as the buoyancy-weight ratio, γ, the relative frequency, f/fN, the Keulegan–Carpenter (KC) number, the reduced velocity, Ur, the Reynolds number, Re, and the generalized Ursells number, on the motion characteristics of the tube, were selectively analyzed, and the reverse feedback mechanism from the tube's motion response to the hydrodynamic loads was confirmed. Finally, the critical hydrodynamic parameters corresponding to the maximum motion response at different values of γ were obtained, and a formula for calculating the hydrodynamic load parameters of the SFT in the motion state was established. The main conclusions of this study are as follows: (i) Under the wave action, the motion of the SFT shows an apparent nonlinearity, which is mainly caused by the intensive interaction between the tube and its surrounding water particles, as well as the nonlinearity of the wave. (ii) The relative displacement of the tube first increases and then decreases with increasing values of f/fN, Ur, KC number, Re, and the generalized Ursells number. (iii) γ is inversely proportional to the maximum relative displacement of the tube and the wave force on the tube in its motion direction. (iv) Under the motion boundary condition (as opposed to the fixed boundary condition), the peak frequency of the wave force on the SFT in its motion direction decreases and approaches the natural vibration frequency of the tube, whereas the wave force perpendicular to the motion direction increases. When the incident wave frequency is close to the natural vibration frequency of the tube, the tube resonates easily, leading to an increased wave force in the motion direction. (v) If the velocity in the Morison equation is substituted by the water particle velocity measured when the tube is at its equilibrium position, the inertia coefficient in the motion direction of the tube is linearly related to its displacement, whereas that in the direction perpendicular to the motion direction is logarithmically related to its displacement. 相似文献