aqwa中文帮助.doc

ANSYS TO AQWA MODEL TRANSLATOR
ANSYS模型文件转换AQWA-LINE标准输入文件
1. INTRODUCTION 引言
It is possible to use classic ANSYS to create an AQWA radiation/diffraction model. Any of the tools available in Workbench or ANSYS can be used to create the model. Once the model is created an AQWA input file can be written out using a macro supplied with ANSYS.
使用传统的ANSYS产生AQWA辐射/绕射模型是可行的。在Workbench或ANSYS中有工具能够建模。一旦模型建立了，使用ANSYS的宏命令'ANSTOAQWA'可以自动产生AQWA-LINE的输入文件（将.aqwa修改为.dat格式即可）。
2. MODEL DESCRIPTION 模型描述
The model must be meshed with the mesh that you wish to use for the AQWA analysis. If you are working from a model created for a structural analysis, it will probably be necessary to re-mesh the model as the structural mesh is likely to be finer than is need for a diffraction analysis.
必须使用与AQWA中分析单元类型相同的单元来划分模型的网格。如果你的模型建于ANSYS结构分析，可能会需要不断重新划分网格直到网格尺寸、数目等满足绕射分析的要求。
There should be a line of nodes at the waterline, although these nodes do not need to coincide with nodes on the structural model. The translation macro will only make diffracting those elements that are entirely below the waterline. If there are no waterline nodes there will be no diffracting elements at the waterline, which will severely reduce the accuracy of the diffraction analysis.
吃水线上应该有一行节点，尽管这些节点不需要符合结构模型的节点。转换宏会仅仅将位于吃水线以下的单元制作成绕射单元（DIFF）。如果没有吃水线节点，则吃水线上不会有绕射单元，这会严重的减少绕射分析的准确性。
All the panel elements below the water must have their normals pointing outwards.
水下所有的面元必须指示外表面。
In AQWA the vertical axis is always the Z-axis. The translator can convert a model with either Y or Z-axes vertical, but the X-axis must be horizontal and preferably should be along the fore/aft axis of the vessel.
在AQWA中垂向轴总是Z轴。转换器能转换一个以Y或Z为垂直方向的模型，但是X轴必须是水平方向的，最好是沿着船的头/尾轴。
If the structure is symmetric and you wish to use the SYMX or SYMY cards in AQWA, you must only select ½ or ¼ of the model as appropriate. If you model a complete vessel and specify X symmetry, the AQWA model will contain two sets of coincident elements.
如果结构是对称的，你希望使用AQWA的SYMX或SYMY卡片,你必须仅仅选择1/2或1/4模型。如果你建立一个完整的船模，指定X方向对称，则AQWA模型将会包含2套一致的单元。
3. ELEMENT MAPPING 绘制单元
The translator maps SHELL41, PLANE42, SHELL43, SHELL63, SHELL181 elements to panels, and PIPE16, PIPE20, PIPE59 elements to TUBEs. It does not recognize any other ANSYS element types. Any material or geometric properties can be used for the shell elements as AQWA does not need any properties at all and the translator does not use them.
转换器能够绘制SHELL41,PLANE42,SHELL43,SHELL63,SHELL181面单元，及PIPE16,PIPE20,PIPE59管单元。它不识别其他任意的ANSYS单元类型。板壳单元使用的任意材料或几何性质，AQWA都不需要，转换器不会使用这些性质。
TUBE elements in AQWA have material density, outside diameter, wall thickness, added mass and drag coefficients, so appropriate properties should be used in the ANSYS model. PIPE59 elements can have added mass and damping coefficients, and these will be transferred. Note that ANSYS uses the inertia coefficient CM, whereas AQWA uses the added mass coefficient CA, where CM = (1+CA). This correction is made automatically by the translator.
AQWA管单元具有材料密度，外径，壁厚，附加质量和阻力系数，所以ANSYS建模时应该定义正确的性质。PIPE59单元具有附加质量和阻力系数，这两项会被转换器写入*.DAT文件。注意：ANSYS使用惯性系数，但是AQWA使用附加质量系数，。转换器会自动修正数据。
4. RUNNING THE MACRO 运行宏命令
When you have created and meshed a model as described above, you can run the macro to generate an AQWA input file. First select the elements that you want to include in the AQWA model.
At the command line type “anstoaqwa” optionally followed by a filename. The AQWA input file will be called “file.aqwa”, where file is the name of your database or the filename you have input.
You will then be prompted to input a number of parameters in a window as shown below.
当你按照上面的描述建立模型并划分网格后，你能够运行转换宏来产生AQWA输入文件。首先选择你想要包含在AQWA模型中的单元。在命令行上输入‘ANSTOAQWA’命令，后面跟一个文件名。AQWA输入文件会是'文件名.aqwa '(实际就是.dat文件）。
接着你会在弹出的如下窗口中输入一系列的参数。
AQWA对网格的要求
Rules for Distribution of Diffraction Plate Elements
The RULES for the distribution of diffraction pressure plate elements over the wetted body surface fall into two categories. These may be classified as rules relating to theoretical considerations and rules relating to numerical computational considerations. The hydrodynamic diffraction/ radiation fluid forces are calculated by using a discrete distribution of fluid SOURCES over the wetted surface of the body (see Section 3.3). These sources are positioned at the centres of the user defined diffraction pressure plate elements. The following rules relate generally to placement and sizing of plate elements which in turn reflects on the distribution of sources.
绕射压力单元在湿表面的分布规则分为两类：考虑理论和数值计算的影响。水动力绕射/入射流体压力是使用整个湿表面上的源离散分布来计算的。这些源定位在用户所定义的绕射压力单元的中心位置。以下的规则主要与压力单元的放置和单元大小有关，反过来会影响源的分布。
(A) RULES due to Theoretical Considerations 基于理论考虑的网格规则
1 The plate elements, which automatically generate sources, MUST COVER the entire mean wetted surface of the body or bodies. The body mean wetted surface is that part of the body which is in contact with the fluid when the body is in an equilibrium or steady state position. This wetted surface must be between the fluid free-surface and the sea-bed.
2 The plates and hence sources, should be CONCENTRATED on those parts of the body which are likely to experience high fluid flow (e.g. the bow section or aft end section of a ship).
压力单元（或源）必须在浮体可能经受较高流体流动的部分分布密集（例如船尾或弓形部分）
3 Plate characteristic dimensions should be LESS THAN 1/7th OF THE INCIDENT WAVE LENGTH. Therefore, the longest side of the plate element should satisfy this criterion.
面元的性能尺寸必须小于突发波高的七分之一，面单元的最长边应该满足这个准则
4 Plate element side dimensions should be LESS THAN the local radius of curvature of the surface body part being modelled. This condition cannot be satisfied at sharp corners and these are effectively rounded off (e.g. knuckles on a ship’s hull).
面元边尺寸应该小于表面的局部曲率半径
5 Diffracting plates modelling the body surface MUST NOT CUT the free surface of the fluid. Plates below the free surface are allowed by AQWA to be denoted as non-diffracting.
6 Plate element normals MUST point outwards from the body surface into the fluid domain. Plate orientations should be checked (using AQWA Graphical Supervisor (AGS)) as AQWA-LINE cannot detect incorrectly placed plates.
7 If the clearance between the body and the sea-bed is large, and using the wave property of exponential decay with depth, parts of the body at a depth greater than approximately 0.5 the wave length may be ignored in the diffraction/radiation calculation. Note that, when employing this economy tactic, the hydrostatic calculation MUST still be performed over the entire wetted body surface, unless the hydrostatic stiffness matrix is input directly by the user. This hydrostatic information may be acquired from AQWA-LIBRIUM or from other sources (e.g. curves of form).
(B) RULES due to Numerical Computational Considerations
1 Element sizes should vary GRADUALLY over the wetted body surface (e.g. larger elements may be used in the parallel mid-body of a ship and gradually decrease in size as the bow or stern is reached).
单元尺寸应该沿湿表面慢慢变化（例如在平行于船体中间部分使用大尺寸单元，在船尾或船艏使用小尺寸单元）
2 Elements should have an aspect ratio of GREATER THAN 1/3. The nearer this is to unity, the better. The aspect ratio of a plate element is defined as follows:
单元应该具有超过1/3的长宽比。这个比值越接近1越好。面元的长宽比定义如下：

3 Element centres, and thus sources, should be at LEAST one element equivalent radius (facet radius) apart. An equivalent radius for any geometrical form of element may be deduced by equating the actual area to that of a circular element of equal area,

4 The centre of a diffraction plate should be MORE THAN a certain distance from the SEA-BED. Obviously, this will depend on the draught of the body and the prescribed water depth. The minimum distance permitted is one half of the element characteristic radius (see Rule 3 above).
5 Adjacent diffraction plate elements should have an area ratio of more than 1/3, e.g. the Adjacent Area Ratio is the MINIMUM of the following:
i-th area / j-th area AND j-th area / i-th area where
2 adjacent elements
Note: Adjacent elements are defined as elements that have common sides.
6 Discretisation of the body should not lead to any gaps in the coverage of the wetted surface and any gaps found (using AQWA-AGS) should be eliminated.
7 The maximum number of elements that may be explicitly defined (on all structures) is 12000, the maximum number of diffraction elements is 8000. The number of plate elements defined relates only to that part of the body being explicitly modelled. Therefore if NF plates are used to model half the body, then two times NF plates will effectively be used for the whole body (effectively four times NF, if using four-fold symmetry).
Thus the maximum TOTAL number of elements that may be defined (including all structures) is 48000 if they are all plate elements. For example a model could have: Tubes 100 not affected by symmetry Total = 100 PMAS 1 not affected by symmetry Total = 1 Non-diffracting 2000 with 2-fold symmetry Total = 4000 Diffracting 3899 with 2-fold symmetry Total = 7798 Total explicitly defined elements = 6000 Total elements in analysis = 11899
8 Try and use the symmetry properties of a body surface to the full. The use of symmetry may only be applied to plate elements.

The translator will then create a complete AQWA-LINE ascii data file that is ready to run in AQWA. However, read the following section carefully.
转换器接着会产生一个完整的AQWA-LINE ascii数据文件（*.aqwa文件）。然而，仔细阅读下面的部分：
5. AQWA-LINE DATA FILE AQWA-LINE数据文件
The file will specify restart stages 1-2 only. It has no options except REST, so AQWA may fail if any of the elements are badly shaped.
这个文件仅指定了重分析阶段是1-2。他除了REST选项外，没有选择其他的选择项，如果存在任意的不理想的单元，则会导致AQWA分析失败。
The total mass is obtained by integrating over the wetted surface area and adding the TUBE masses, so it should be reasonably accurate. However, the integration used is not as accurate as that in AQWA so there may be a small difference between the weight and buoyancy, particularly if tubes represent a large portion of the model.
总质量由湿表面区域和附加管的质量整体累加得到，所以它理论上是准确的。然而，在AQWA中并不是那么准确的累加，所以高度和浮力会有微小的差别，尤其是软管占据了模型的一大部分。
The position of the CG is unknown. A point mass is placed at the water-line above the CB, but you should change this to the correct position.
重心坐标的位置未知。一个质量点替代性的放在浮心以上的水线上，但是你应该改变此质量点到正确的位置。
The moments of inertia are estimated based on the overall dimensions of the model and using standard formulae for a ship. You should change these to the correct values.
惯性矩的评估基于模型整体的维度及船体使用的标准计算公式。你应该修改默认值为正确的值。
The maximum frequency is calculated from the maximum side length of the underwater elements. The range of frequencies runs from 0.1Hz to the calculated maximum, in steps of 0.1Hz.
最大频率是由水下单元的最大边长度计算得到的。频率的范围是从0.1Hz增加至最大频率，步长0.1Hz。
The directions are in steps of 15°, over a range that is determined by the symmetry you have specified, in accordance with the requirements of AQWA.
方向的步长默认为15°，具体范围与你定义的对称性有关，同时需符合AQWA的要求。SYMX : 0°—180°或-180°—0°
SYMY : -90°—90°
SYMX,SYMY : 0°-90°
AQWA综述
AQWA是一个由AQWA-LINE（常规波的衍射/辐射频域计算），AQWA-LIBRIUM（大型锚泊结构包含系泊索的初始静、动稳定性计算），AQWA-FER（不规则波频域计算），AQWA-DRIFT（包含慢漂流的随机波时域计算），AQWA-NAUT（规则波和不规则波的非线性时域计算），AQWA-Cable Dynamics（耦合缆索动力学），等模块构成的完整集成系统。这些模块统一封装在强大的AQWA图形用户界面AQWA-GS中。
AQWA-Cable Dynamics（耦合缆索动力学）一个可选择的集成模块，用于在频域和时域中耦合缆索动力学的计算；AQWA-WAVE是AQWA和ASAS、ANSYS间的联接程序，用于传递运动和压力载荷。

AQWA FILES
AQWA的文件类型
The AQWA Suite uses both ASCII files and binary files for its input and output. All the files are defined by a generic name with a 3 character file extension. The maximum length of the filename is 28 characters (32 with the extension). It is strongly recommended that the filename is related to the program used.
AQWA程序使用ASCII和二进制两种格式的文件做输入和输出。所有的文件由一类3个字母的后缀名定义。文件名最大长度是28个字母。推荐文件名与所使用的程序有关。
The extension names are related to the file type. The following is a list of the file extension names commonly used in AQWA and AQWA Graphical Supervisor (AGS).
后缀名与文件类型有关。下列是AQWA和AQWA-GS使用到的文件类型列表。
Input Files输入文件
*.DAT -- ASCII file for model definition and analysis parameters. Used by all AQWA programs.
DAT是一种ASCII类型文件，文件信息：定义AQWA模型的节点与单元及分析参数，可以被AQWA的所有程序读取。
*.XFT -- ASCII file defining a time history of external force on a structure or structures in six degrees of freedom in local axis system. Used for time domain analysis (optional).
XFT是一种ASCII文件，文件信息：定义局部坐标系下的具有6个自由度的结构在一段时间历程中所受的外力，该文件用于AQWA的时域分析（可选择的）
*.WVT -- ASCII file defining a time history of wind velocity and direction. Used for time domain analysis (optional).
WVT是一种ASCII文件，文件信息：定义一段时间历程中的风速和风向，该文件用于AQWA的时域分析（可选择的）
*.LIN -- ASCII file defining ship offsets. Used by AGS Mesh Generator to define hull shape.
LIN是一种ASCII文件，文件信息：定义了船舶的船线坐标，该文件用于AGS Mesh Generator直接产生船体网格。AGS Mesh可以将网格另存为.DAT文件。
*.MSD -- ASCII file defining the mass distribution of a vessel. Used by AGS for shear force and bending moment calculation.
MSD是一种ASCII文件，文件信息：定义船舶的质量分布，该文件用于AGS计算剪切应力和弯矩。
*.EQP -- Binary file containing the equilibrium positions of structures. Created by AQWA-LIBRIUM and used (optional) by FER, DRIFT or NAUT; see RDEP option.
EQP是一种二进制文件，文件信息：包含了结构的平衡位置，由AQWA-LIBRIUM创建， 被FER,DRIFT及NAUT子程序使用；（见RDEP选项
Output Files输出文件
*.LIS -- ASCII file containing model definition/analysis parameters and the analysis results.
LIS一种ASCII文件，包含了模型的定义、分析参数和分析的结果
*.HYD -- Binary file containing the hydrodynamic results calculated in AQWA-LINE. Can be used for further AQWA analysis.
HYD一种二进制文件，包含了AQWA-LINE水动力计算结果，可以被利用做进一步的AQWA分析
*.RES -- Binary file containing the model definition/analysis parameters and the hydrodynamic results calculated in AQWA LINE. Can be used for further AQWA analysis or structure visualisation etc in AGS.
RES一种二进制文件，包含模型的定义/分析参数和AQWA-LINE的水动力计算结果，可以做进一步的AQWA分析或者在AGS中可视化显示结构模型
*.EQP -- Binary file containing the equilibrium positions of structures. Created by AQWA-LIBRIUM and used (optional) by FER or DRIFT; see RDEP option.
EQP是一种二进制文件，文件信息：包含了结构的平衡位置，由AQWA-LIBRIUM创建，被FER,DRIFT及NAUT子程序使用；（见RDEP选项）
*.ENL -- Binary file containing Morison element/nodal loading. Only created for TETHER analysis, or tube elements at analysis stage 6.
ENL是一种二进制文件，文件信息：包含了单元/节点的Morison荷载。只能由TETHER分析或者管单元分析时的第六步创建。
*.MES -- ASCII file containing messages issued during an AQWA analysis.
MES是一种ASCII文件。文件信息：包含了AQWA分析时的警告信息和错误信息。
*.POS -- Binary file containing structures' positions at each time step. Used by AGS for generating animation.
POS是一种二进制文件，包含了结构在每个时间步的位置。POS文件被AGS使用以产生动画。
*.PLT -- Binary file containing AQWA analysis results. Used by AGS for plotting graphs.
PLT是一种二进制文件，包含了AQWA分析的结果。PLT被AGS使用以画出图表。
*.POT -- Binary file containing potentials. Used by AGS or AQWA-WAVE for element pressure calculation. This file is only created by AQWA-LINE when LDOP option is on.
POT是一种二进制文件，AGS或AQWA-WAVE用POT文件来计算单元的压力。当LDOP选项被选中时，AQWA-LINE产生这个文件。
*.USS -- Binary file containing source strengths. Used by AQWA-WAVE for Morison force calculation. This file is only creat