单桨船模自航试验的相似准则与模拟方法

本文提出一种新的船模自航模型化方法以“消除”船－桨干扰总理２的惊工影响，首先讨论船－桨组合体绕流（平均流动）应满足的相似准则，其中引进了两个新的准则以联系船 尾流的特征；尾流宽度与速度亏损，讨论了满足这些准则的模拟条件和方法，给出满足相似条件的船模－实船性能关系式，最后讨论了新模拟方法在船旋螺旋桨空的与噪声模型试验中的应用。     

一种基于体积力螺旋桨模型的自航计算方法

文章以集装箱船模型KCS(KRISO Container Ship)为研究对象,基于通用CFD软件FLUENT 12.0.16,采用螺旋桨体积力模型,实现了模型尺度下实船自航点的全粘带自由面计算。该文的计算包括静水拖航计算、自航计算,以及扭矩对自航计算结果的影响分析。通过与试验值的分析比较,验证了该方法的有效性。由于采用了完全结构化的六面体网格,带对称面的计算域单元数仅为33万。研究结果还表明:考虑扭矩的全流场计算对于改善流动细节,获得更精确的计算结果是有利的,但计算量有所增加。     

多桨船舶自航因子数值预报

以某四桨水面船舶为研究对象,基于RANS方法和滑移网格技术,建立船、附体和螺旋桨整体计算模型,并运用小范围改变螺旋桨转速的方法和前后桨分别计算的方法预报该船的自航因子。结果表明：四桨船舶内、外桨的自航因子并不相等,内后桨的实效伴流分数和推力减额分数均比外前桨的大;提出的方法计算结果可靠,能够体现四桨船舶自航因子的差异性,并且符合推力减额与伴流关系的一般规律,可为多桨船舶的自航试验提供依据。     

耙吸挖泥船拖力预报研究

在单桨船自航性能预报二因次与三因次标准方法与规范的基础上,提出一种耙吸拖力自航试验及实船耙吸拖力预报方法。选取5条不同型号的双桨耙吸挖泥船进行模型试验,分别用二因次与三因次方法对耙吸拖力进行预报。根据预报结果对三因次法中的功率因子与转速因子进行回归分析,比较两种方法的最终预报结果,验证了所提方法的合理性、有效性。     

Self-propulsion computations using a speed controller and a discretized propeller with dynamic overset grids

A method that can be used to perform self-propulsion computations of surface ships is presented. The propeller is gridded as an overset object with a rotational velocity that is imposed by a speed controller, which finds the self-propulsion point when the ship reaches the target Froude number in a single transient computation. Dynamic overset grids are used to allow different dynamic groups to move independently, including the hull and appendages, the propeller, and the background (where the far-field boundary conditions are imposed). Predicted integral quantities include propeller rotational speed, propeller forces, and ship’s attitude, along with the complete flow field. The fluid flow is solved by employing a single-phase level set approach to model the free surface, along with a blended k−ω/k−ɛ based DES model for turbulence. Three ship hulls are evaluated: the single-propeller KVLCC1 tanker appended with a rudder, the twin propeller fully appended surface combatant model DTMB 5613, and the KCS container ship without a rudder, and the results are compared with experimental data obtained at the model scale. In the case of KCS, a more complete comparison with propulsion data is performed. It is shown that direct computation of self-propelled ships is feasible, and though very resource intensive, it provides a tool for obtaining vast flow detail.     

基于滑移网格的带桨水面船自航性能预报研究

应用FINE/Marine软件对KCS船、KP505桨以及考虑自由液面的船桨组合体进行数值计算,并计算其自航性能。利用滑移网格技术和随体网格来实现船桨之间的相互耦合。考虑到原有的自航性能数据处理方法并不代表实际情况,文中借鉴强制自航法的概念提出了一种新的船舶自航点求解方法预报船舶自航性能,并与模型试验结果进行比较,吻合良好,其中推力减额系数、伴流分数以及船舶推进效率的计算误差分别为0.5%、2.18%、6.76%。本文研究为预报船舶自航性能提供了一种新的研究手段。     

RANS simulation of a container ship using a single-phase level-set method with overset grids and the prognosis for extension to a self-propulsion simulator

Steady flow simulations for the Korean Research Institute for Ships and Ocean Engineering (KRISO) container ship (KCS) were performed for towing and self-propulsion. The main focus in the present article is on the evaluation of computational fluid dynamics (CFD) as a tool for hull form design along with application of state-of-the-art technology in the flow simulations. Two Reynolds-averaged Navier-Stokes (RANS) equation solvers were employed, namely CFDShip-Iowa version 4 and Flowpack version 2004e, for the towing and self-propulsion cases, respectively. The new features of CFDShip-Iowa version 4 include a single-phase level-set method to model the free surface and an overset gridding capability to increase resolution in the flow and wave fields. The new features of Flowpack version 2004e are related to a self-propulsion scheme in which the RANS solver is coupled with a propeller performance program based on the infinitely bladed propeller theory. The present work is based on a close interaction between IIHR-Hydroscience and Engineering of the University of Iowa and Osaka Prefecture University. In the following article, overviews are given of the present numerical methods and results are presented and discussed for the KCS in towing and self-propulsion modes, including comparison with available experimental fluid dynamics (EFD) data. Additional evaluation is provided through discussion of the recent CFD Workshop Tokyo 2005, where both methods appeared to yield very promising results.     

舵桨相互作用下现代船舶绕流数值研究（英文）

Reducing the fuel consumption of ships presents both economic and environmental gains. Although in the past decades,extensive studies were carried out on the flow around ship hull, it is still difficult to calculate the flow around the hull while considering propeller interaction. In this paper, the viscous flow around modern ship hulls is computed considering propeller action. In this analysis, the numerical investigation of flow around the ship is combined with propeller theory to simulate the hull-propeller interaction. Various longitudinal positions of the rudder are also analyzed to determine the effect of rudder position on propeller efficiency. First, a numerical study was performed around a bare hull using Shipflow computational fluid dynamics(CFD) code to determine free-surface wave elevation and resistance components.A zonal approach was applied to successively incorporate Bpotential flow solver^ in the region outside the boundary layer and wake, Bboundary layer solver^ in the thin boundary layer region near the ship hull, and BNavier-Stokes solver^in the wake region. Propeller open water characteristics were determined using an open-source MATLAB code Open Prop, which is based on the lifting line theory, for the moderately loaded propeller. The obtained open water test results were specified in the flow module of Shipflow for self-propulsion tests. The velocity field behind the ship was recalculated into an effective wake and given to the propeller code that calculates the propeller load. Once the load was known, it was transferred to the Reynolds-averaged Navier-Stokes(RANS) solver to simulate the propeller action. The interaction between the hull and propeller with different rudder positions was then predicted to improve the propulsive efficiency.     

浅吃水肥大型船的尾部线型研究

从分析船舶尾部伴流场对船舶阻力推进,操纵及船体振动性能等影响的观点,研究尾部三维伴流场,介绍尾型与伴流场之间关系及非对称双尾鳍船型的形成。非对称双尾鳍船型与优选的常规双尾鳍船型模型的阻力,自航及伴流场等比较试验结果表明,非对称双尾鳍船具有两大优点,首先,该船型能在浆前方产生一个与外旋浆旋向相反的预旋流,在保持了优良阻力性能前提下可提高外旋浆推进效率8％,获得阻力,推进,操纵各性能间的最佳配合,第二,轴向伴流分布比较均匀,满足BSRA5项衡准指标,改善了螺旋浆工作的流场条件,减少了螺旋浆产生空泡及其诱导船体激振的危险,使节能与减振得到统一,最后还介绍了该船型首制船“宁安1号”的实船测试结果及其由船模试验预报实船性能的一致性。     

数值水池船模自航试验方法研究

同时考虑自由液面、真实螺旋桨的旋转运动,在数值水池实现了船/桨整体流场的数值计算。在既定航速下,推力与船体阻力为螺旋桨转速的函数,通过变化转速得到自航点。文中数值计算得到的自航点与物理水池试验自航点吻合良好。根据数值自航试验结果,不仅可通过积分的方法计算伴流分数与推力减额分数,还可详细分析螺旋桨进流与桨叶的速度、压力分...     

船体影响下舵附推力鳍的节能效果研究

通过 CFD方法实现船舶自航试验模拟,计算在船体影响下舵附推力鳍可带来2.3%左右的节能效果,分析指出舵附推力鳍通过吸收螺旋桨尾流能量,增加螺旋桨推力,改善船尾伴流,降低船身阻力的节能原理。计算敞水状态下桨/舵/舵附推力鳍系统的推进性能,并与船体影响下的推进性能进行比较,指出敞水状态下舵附推力鳍的工作状态与在船体影响下有着较大不同,为设计人员提供基础参考。     

Circular motion tests and uncertainty analysis for ship maneuverability

Circular motion test data and uncertainty analysis results of investigations of the hydrodynamic characteristics of ship maneuvering are presented. The model ships used were a container ship and two tankers, and the measured items were the surge and sway forces, yaw moment, propeller thrust, rudder normal and tangential forces, pitch and roll angles, and heave. The test parameters were the oblique angle and yaw rate for the conditions of a hull with a rudder and propeller in which the rudder angle was set to zero and the propeller speed was set to the model self-propulsion conditions. Carriage data showing the accuracy of the towing conditions in the circular motion test are also presented. It was confirmed that the uncertainties in the hydrodynamic forces such as the surge and sway forces, yaw moment, rudder tangential and normal forces, and propeller thrust were fairly small. The reported uncertainty analysis results of the circular motion test data may be beneficial in validating data quality and in discussing reliability for simulation of ship maneuvering performance.     

基于CFD方法的6500TEU集装箱船舵空泡腐蚀数值模拟研究

舵的空泡腐蚀研究在船型优化设计和新船型开发中具有重要意义。文章以6 500 TEU集装箱船的NACA0021舵为研究对象,通过对船、桨、舵整体三维建模,运用CFD方法在3D计算域下对舵的非定常空化现象进行数值模拟,得到了与试验比较一致的结果。同时还对改善舵空蚀现象的措施进行了分析。研究表明,通过整体建模的数值模拟方法对舵空泡性能进行预测研究,其结果是合理可信的。     

几何相似模型推进性能的尺度效应及相关分析

本文通过五艘几何相似船模的常规阻力试验、螺旋桨模型敞水试验、自航试验以及其中三艘船模的伴流场测量,分析研究了五艘船模的阻力、螺旋桨敞水性能及自航要素间的尺度效应问题。探讨了自航要素尺度效应的缘由。取得了伴流分布尺度效应较满意的结果。并用各种相关方法同相应的实船试航资料进行相关分析,明确了采用不同相关方法对阻力及各自航要素的影响。     

船艇波浪中自航试验研究

对一艘船艇作了波浪中自航试验研究，得到了规则波中自航因子变化曲线，用直接功率法作了失速预报，并用谱分析法预报了该艇的纵摇、升沉及螺旋桨出水概率。本文的重要结论：船艇在波浪中的自航因子在简化处理时，可以认为相当于静水中的自航因子。     

船桨干扰定常空化性能数值模拟

文章采用CFD技术计算了船桨干扰定常空化性能。首先计算了不同空化数下的NACA66(MOD)水翼和DTRC4381螺旋桨的定常空化性能,同时预报了KCS船的伴流场、阻力性能和船体表面压力分布。为了验证计算船后螺旋桨空化流的可行性,文中对KCS船和KP505螺旋桨进行了整体考虑,并计算了不同空化数下的船后螺旋桨的空化覆盖面积。计算表明,文中采用的计算方法合理,计算结果与试验结果吻合。     

Numerical calculations of propeller shaft loads on azimuth propulsors in oblique inflow

This paper evaluates various computational methods used to compute propeller performance, hydrodynamic side force and bending moment applied to an azimuth propulsor propeller shaft in oblique inflow. The two non-viscous models used are the BEM method and the blade element momentum theory (BEMT). RANS calculations are used to compute the loads on the propeller and the nominal wake velocity from the thruster body to be used in the BEMT model. The effect of the ship hull is also considered in the calculation by implementing the measured nominal wake of a ship hull at different propeller azimuthal positions. All the models are compared and validated against the experimental results, and the discussions are presented.     

螺旋桨噪声的无量纲化研究

实船和船模的螺旋桨噪声存在一定的相似性,通过无量纲分析船模螺旋桨噪声可以预报实船的螺旋桨噪声。本文利用无量纲分析方法,得到影响螺旋桨噪声的一些因素,如雷诺数、桨直径、桨转速、频率、空泡数等。在此基础上对这些因素进行分析,并提出修正方法。     

New method for predicting full-scale power performance of pumpjet propulsion system based on statistical learning北大核心CSCD

[目的]针对“适配于螺旋桨的船尾线型+泵喷推进器”构成的船舶泵喷推进系统,提出一种基于统计学习的实船快速性预报新方法。[方法]以某大型水面船舶泵喷推进系统为对象,通过神经网络学习典型推进泵的推力系数图谱曲线,综合运用船-桨配合时的K_(T)-J曲线和船体-喷泵配合时的推力特性曲线,建立“仅需船舶阻力曲线就能实现船舶泵喷推进系统实船快速性预报”的新方法,并基于船模阻力试验、泵喷模型敞水试验及船体-泵喷自航试验的测量换算结果对实船推进性能的预报结果开展精度校验。[结果]校验结果表明:在航速18~30 kn范围内,船舶泵喷推进系统的自航转速、推力和功率的预报误差可控制在5.4%以内,其中设计航速附近的误差甚至小于2%;船体-泵喷的相互作用程度介于船-桨与船体-喷泵之间且幅值相对较小,推力减额系数为趋向于0的极小值,故船舶泵喷推进系统是介于桨轴推进系统和喷水推进系统之间的产物。[结论]该预报方法有利于提升船舶泵喷推进系统实船快速性预报的能力,可为新型舰艇泵类推进系统总体设计/研究提供参考。     

船用螺旋桨鸣音的研究

本文根据某船螺旋桨的噪声测量和激振试验结果,描述了螺旋桨鸣音的特点和产生鸣音的机理。 为了预报实桨的鸣音,按照作者提出的模拟条件,在空泡水筒中进行了模型试验。 文中还提出了几种消除鸣音的方法。经实船试验,证明这些方法是有效的。