fluent udf中文帮助
fluent udf中文帮助本章简要地介绍了用户自定义函数(UDF)及其在 Fluent 中的用法。在 1.1 到 1.6 节中我们会介绍一下什么是 UDF；如何使用 UDF，以及为什么要使用 UDF，Makefile udfmakefile udf2DEF INE PROPERTYDEFINE DRIFT DI AM基础输运方程单元()面,区域()和线(操作求解器数据运仃输运方程求解器建立在有限容积法的基础上,这种方法将计算域离散为有限数目的控制体或是单元。网格单元是中基本的计算单元,这些单元的守恒特性必须保证。也就是说普通输运方程,例如质量,动量,能量方程的积分形式可以应用到锊个单元:/pad+,p·dA=中 TODa+/,SwAunsteadyeonv画 ctiondiffusiongeneration此处,是描述普通输运数量的变量()根据所求解的输运方程它可取不同的值。下面是在输运方程中可求解的的子集E守恒与否需要知道通过单元边界的通量。因此,需计算出单元和面上的属性值(单元()面,区域()和线(单元和单元面被组合为一些区域(),这些区域规定了计算域(例如,入口,出口,壁面)的物理组成)。当用户使用的时,用户的叮调用流体区域或是边界区域的计算变量(需要获得适当的变量,比如说是区域参考)和单元,以便标定各个单元。区域)是一群单元或单元面的集合,它可以由模型和区域的物理特征(比如入∏,出∏,壁面,流伓区域)来标定。例如,·些被指定为面域()的单元面可以被指定为类型,由此,速度也就可指定了。线()是据结构的内部名称,可被用来指定一个区域结构可作为数据储存器米使用,这些数据对于它所表示的单元和面来说是公用的(操作多数的任务需要在一个线的所有单元和面上重复执行。比如,定义一个自定义轮廓函数()则会对一个面线上)的所有单元和面进行循环。为了用户方使向用户提供了一些循环宏工具(来执行对单元,面,节点()和线()的重复操作例如,单元循环宏()可以对给定单元线上的所有单元进行循环操作()。而面循环宏()则可调用所有给定面线()的面。提供的循环工具请见在某些情况下需要对某个变量操作,而这个变量恰恰又不能直接被当作变量来传递调用。比如,如果用户使用宏来定义,求解器将不会向它传递指针。这种情况下,用户函数需要用提供的宏来调用线指针(见求解器数据通过用户界面将函数(它已被编译和连接)连接到求解器上可实现调用求解器变量。旦和求解器正确连接,无论何时,函数都可调用求解器数据。这些数据将会被作为用户变量自动地传递给注意,所有的求解器变量,不管是求解器传递给的,还是传递给求解器的,都使用单位。运行将会在侦定时刻被调用。但是,也可对它们进行异步执行,使用宏,还可在需要时()执行。详情请见解释和编译的比较编译和的构建方式一样。脚木被用来调用编译器来构建一个当地目标代码库()。目标代码库包含高级语言源代码的机器语言翻译。代码库在运行时由“动态加载”()过程连接到上。连接后,与共亨库的联系()将会被保存在用户的文件中这样,当以后再读入文件时,此编译库将会与自动连接。这些库是针对计算机的体系结构和·定版本的使用的。所以,当更新,或计算机操作系统改变,或是在不同类型的机器上运行时,这些库必须重新构建而解释则是在运行吋,直接从语言源代码编译和装载()。在运行中,源代码被编译为中介的独立于物理结构的使用预处理程序的机器代码(被调用时,机器代码由內部仿真器(),或注释器)执行。注释器不具备标准编译器的所有功能;它不支持语言的某些原理。所以,在使用吋,有语言限制(见)。例如,不能够通过废弃结构()来获得数据。要获得数据结构,必须使用由提供的预定义宏。另一个例子是不能识别指针数组。这些功能必须由来执行。编译后,用户的函数名称和内容将会被储存在文件中。函数将会在读入文件时被自动编译。独立于物理结构的代码的外层()叮能会导致执行错误(),但却可使共亨不同的物理结构,操作系统,和版本。如果运行速度较慢,不用被调节就可以编译代码的形式(运行中的和请见选择或是时,注意以下内容:对其它平台是便捷的(可作为()来运行不需编译器。慢需要较多的代码。在使用语言上有限制。不能与编译系统或用户库()连接。只能使用预定义宏来获得结构中的数据。(见和)比运行快在使用语言上不存在限制可用任何编译器编译。能调用以其他语言编写的函数机器物理结构需要用户建立的每个版本的共享库(如果包含有注释器()不能处理得语言元素,则不能作为)运行总的来说,当决定使用那种类型的时使用作为简单的函数使用作为复杂的函数,这些函数对有较大要求(例如每次运行时,在每个单元上均须调用的属性需要使用编译库一个例子编辑代码,并且在用户的模型中有效使用它,须遵循以卜七个基木步骤定义用户模型。编制语言源代码。运行读入,并设置文件。编译或注释()语言源代码。在中激活开始计算。分析计算结果,并与期望值比较。在开始解决问题前,用户必须使用定义希望解决的问题()。例如,加入用户希望使用来定义一个用户化的边界条件()。用户首先需要定义一系列数学方程来描述这个条件。接下来用户需要将这些数学方程(概念设计)用语言写成一个函数)。用户可用文本编辑器米完成这一步。以为后缀名米把这个文件保存在工作路径下。写完语言函数后,用户即可运行并且读入或设置文件()。对C语言源代码进行注释,编译,和调试),并在中激活用户函数()。最后,运行计算(),分析结果并与期望值比较。()。根据用户对结果的分析,可将上述整个过程重复几次。具体如下。定义用户模型生成和使用的第一步是定义用户的模型方程。如图所示的涡轮叶片。模拟叶片冑围的流玚使用了非结构化网格。计算域由底端的周期性边界()延伸到顶端的相同部分(),速度入口在左边,压力出口在右边。Irvine ua〔15512405危e893nde5)文中对入口速度为常数分布和抛物线分布的流场进行了比较。分段线性的分布可由边界场选项得到(),而多项式分布则只能使用用户自定义函数得到。进口速度为常数()的结果如图1.7.2和1.7.3所示。当流动沿着涡轮叶片进行时,初始速度场被改变了。了4101265105 tces. 89E.11电+01Turbine vane〔1551cl,2405他e,的93nde引假定现在要设涡轮叶片入∏速度不是常数值,其分布如下2un=20-2000745士变量在入口中心处为0.0,在入口上部和下部则分别为而入口中心处的速度为边界上为0。用户可用描述这一分布,并将它应运到模型中来解决这类问题。编制语言源代码。选定方程定义后,用户可用任意文本编辑器来书写C语言代码。以扩展名保存源代码文件保存到工作路径下。关于的书写请参考下面是一个怎样在中应用方程的例子。的功能由主要的宏()米定义。此处,宏用来表示下面的代码旨在给求解器捉供边界的轮廓信息。书中将在以后部分讨论其它的宏宏的第一个变量用来定义速度入口面板中的函数。名称可任意指定。在给定的边界区域上的所有单元面()上将会使用函数的这个方程。当用户在用户界面选定作为边界条件时,将会自动定义线()。下标由应用程序自动定义。中被用来形成对边界区域上所有单元面的循环()。对于每个面,面的质心()的坐标可由宏来获得。抛物线方程中用到了坐标,速度值通过宏来返回给面。宏和宏都是提供的宏。详情请见5读入,并设置文件建立后,用户开始设置在工作路径下启动读入(或设置)文件(如果文件以前设置过,请确认它是否被保存在了工作路径编详或注释()语言源代码这部分将例中的源代码作为来编译。注意,这个例子不可应用于的并行网络()。完整的编译和连接请见确认的文件(如果以前设置过)和语言源代码在工作路径卜。用面板编译例如, ud fexamp leInterpreted UDFSSource file rlameample+CCPP Command nameStack sizeH Display Assembly ListingH Use Contributed CPPCompilecospHelp在下键入语言源代码文件例如, udfexample.c。如果用户源代码不在目前工作路径下,则在编译,需在面板中间如文件完整的路径。在栏里,选择预处理器。省设置为如果用户函数的局部变量数目大于将会导致堆栈溢出。这种情況下,应将设置为比局部变量大的数
- 2020-11-04下载
- 积分：1
Principles of Mobile Communication Third Edition
Gordon L. Stüber著，为英文原文第三版。其第二版已经翻译成中文，即为移动通信原理（第二版），由电子工业出版社出版，但翻译水平很差。Gordon L. StuberPrinciples of mobileCommunicationThird edition② SpringerGordon L. StuberGeorgia Institute of TechnologyAtlanta gaUSAstuber @ece gatech. eduISBN978-1-4614-0363-0e-ISBN978-1-46140364-7DOI10.1007/978-1-46140364-7Springer New York Dordrecht Heidelberg londonLibrary of Congress Control Number: 2011934683C Springer Science+Business Media, LLC 2002, 2011All rights reserved. This work may not be translated or copied in whole or in part without the writtenpermission of the publisher(Springer Science+ Business Media, LLC, 233 Spring Street, New York,NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use inconnection with any form of information storage and retrieval, electronic adaptation, computer softwareor by similar or dissimilar methodology now known or hereafter developed is forbiddenThe use in this publication of trade names, trademarks, service marks, and similar terms, even if they arenot identified as such, is not to be taken as an expression of opinion as to whether or not they are subjectto proprietary rightsPrinted on acid-free paperSpringerispartofSpringerScience+businessMedia(www.springer.com)To Alana, our son nickolasmy father lothar Stuiberand my late mother Beatrice stiiberPrefacePrinciples of Mobile Communication, third edition, is a major revision of thesecond edition. Like its earlier editions, this book provides a mathematicallyrigorous overview of physical layer wireless communications. The basic pedagogicmethodology is to include fully detailed derivations from first principles. The text isintended to provide enough principle material to guide the novice student, whilit the same time having plenty of detailed material to satisfy graduate studentsinclined to pursue research in the area. The book is intended to stress the principlesof wireless communications that are applicable to a wide array of wireless standardsIt is intended to serve as a textbook and reference for graduate students, and a usefulreference for practicing engineersOrganization of the bookChapter 1 begins with an overview that is intended to introduce a broad array ofissues relating to wireless communications. Included is a brief description of theevolution of various wireless standards, the basic concepts of cellular frequencyreuse, the land mobile radio propagation environment, link budgets, and coverageand capacity of cellular radio systemsChapter 2 provides an extensive treatment of radio propagation, since goodunderstanding of the physical wireless channel is essential for the developmentand deployment of wireless systems. The chapter begins with a treatment ofthe narrow-band faded envelope for conventional fixed-to-mobile channels foundin cellular radio systems, mobile-to-mobile channels found in mobile ad henetworks, and multiple-input multiple-output (MIMO) channels where multipleantennas are used at both the transmitter and receiver to achieve high capacity afterconsidering the narrow-band channel, we consider the statistical treatment of wide-band channels. The emulation of wireless channels is essential for the developmentand testing of wireless systems, and the chapter provides a detailed discussion ofchannel simulation techniques. Finally, the chapter concludes with a discussion ofshadowing and path loss models for land mobile radio environmentsPreraceChapter 3 provides a detailed treatment of co-channel interference which is therimary impairment in spectrally efficient cellular frequency reuse systems. Veryoften the receivers in such systems are affected by multiple co-channel interferersand the probability distribution of the total interfering power is considered. Thchapter also considers the link outage performance due to co-channel interferencein a variety of wireless environmentsChapter 4 covers the various types of modulation schemes that are used in mobilecommunication systems along with their spectral characteristics. The chapter beginswith the mathematical representation of bandpass modulated signals, along withNyquist pulse shaping. Later, a large variety of modulation schemes used in wirelesssystems are considered, including both single-carrier and multi-carrier modulation,and both linear and nonlinear modulation techniques This is followed by a treatmentof the power density spectrum of modulated signals. Although quite mathematicalin nature, power spectrum is an important topic, since wireless systems are requiredto operate within a specified out-of-band emission maskChapter 5 discusses the error probability performance of various digital modulation schemes on narrow-band fat fading channels. The performance is evaluatedwith a variety of receiver structures, including coherent detectors, differentialcoherent detectors and noncoherent detectorsChapter 6 includes a treatment of multi-antenna techniques for combatingenvelope fading. The chapter includes a discussion of various diversity combiningtechniques for coherent, differentially coherent, and noncoherent receiver detectionof signals on fading channels with additive white gaussian noise. also consideredis optimal combining which is effective when the primary additive impairment isco-channel interference rather than noise. Finally, the chapter considers the use ofmultiple antennas at the transmitter in the context of classical beam-forming andtransmit diversityChapter 7 provides an extensive treatment of digital signaling on intersymbolinterference(ISI) channels that are typical of broadband land mobile radio systemsThe chapter begins with the characterization of Isi channels and goes on todiscuss techniques for combating ISI based on symbol-by-symbol equalization andsequence estimation. Later, error probability for maximum likelihood sequenceestimation is considered. The chapter concludes with a discussion of co-channeldemodulation for the purpose of mitigating co-channel interference on Isi channelsChapter 8 covers error control coding techniques for wireless systems. Thechapter begins with a discussion of basic block coding including space-time blockcodes Convolutional coding is considered next along with the Viterbi and BCJRalgorithms for decoding convolutional codes, followed by trellis coded modulationThe chapter then provides a detailed discussion on the design and performanceanalysis of convolutional and trellis codes for awgn channels, and interleaved fatfading channels, and fading isi channels. Later, space-time trellis codes are treatedand the chapter concludes with Turbo codinChapter 9 is devoted to spread spectrum techniques The chapter begins with anintroduction to direct sequence and frequency hop spread spectrum. This is followedy a detailed treatment of spreading sequences. Also included is a discussionPrefaceof the effects of tone interference on direct sequence spread spectrum, and theRAKE receiver performance on wide-band channels. The chapter wraps up witha discussion of cdma multiuser detectionChapter 10 is devoted to multi-carrier techniques. It considers the performanceof ofdm on frequency-selective channels and considers the effect of residualISI and problem of residual ISI cancellation. Later, the chapter examines singlecarrier frequency-domain equalization(SC-FDE)techniques. This is followed by atreatment of orthogonal frequency division multiple access (OFDMA)on both theforward and reverse links. The chapter concludes with a discussion of single-carrierfrequency division multiple acceSs (SC-FDMA)Chapter 11 considers frequency planning techniques for cellular systems. Thechapter begins with a discussion of cell sectoring, cell splitting, and reuse partition-ing. Later, the chapter considers radio planning for OFDMa cellular systems. Thisis followed by hierarchical overlay/underlay architectures based on cluster planningFinally, the chapter wraps up with macrodiversity TDMA cellular architecturesChapter 12 considers CDMa considers CDMA cellular systems, consideringtopics such as capacity and power control This is followed by a discussion ofhierarchical macrodiversity CDMa architectures and their performanceChapter 13 is devoted to cellular radio resource management. The chapter beginswith an introduction to basic hard and soft handoff. Later, the chapter considers theimportant problem of link quality evaluation, including signal strength averaging,velocity estimation, and velocity adaptive hard handoff algorithms later, a detailedanalysis of hard and soft handoff is provided. Finally, the chapter wraps up withmethods for estimating received carrier-to-interference plus noise ratio(CINR)The Appendix includes a brief and focused tutorial discussion of probabilityand random processes. A good understanding of the material in the Appendix isessential, since the concepts are widely used throughout the textUSing This Book for InstructionThe book has been developed from a graduate-level course on physical wirelesscommunications that I have taught at Georgia Tech since 1993. Normally, I prefera graduate-level course in digital communications as a prerequisite for this courseHowever, such a prerequisite may be waived to the extent that there is extensivebackground material in each chapter. A course may cover the introductory materialin each chapter and skip the more specialized material. In my own classes, I alwaystry to judge the mathematical level of the students early and adapt accordinglyThe book obviously contains far too much material to be taught in a onesemester course. However, i believe that it can serve as a suitable text in mostsituations through the appropriate instructor selection of background sections. Myown preference for a one semester course is to include the following material inorder: Chap. 1, Chap 2(skipping the more advanced material), and the first twosections of Chap 3. In moving to modulation waveforms in Chap. 4, an instructormay have to treat/assume basic signal-space representation. However, most students
- 2020-12-09下载
- 积分：1
