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profoil-万维网 An Overview of PROFOIL-WWW 纵观profoil-万维网 PROFOIL-WWW is a Web version of PROFOIL - the author's low-speed airfoil design code. profoil--WWW的网站是一个版本profoil-作者的低速翼型设计规范. From the outset it must be stated that PROFOIL is not an all inclusive airfoil-design package. 从一开始就应该说明,并不是所有的包容profoil机翼设计方案. Inverse design, as later discussed, is its strength; analysis is not - it has none. 反设计,后来谈,是其实力;分析不是-它没有. In fact, the airfoil performance characteristics (viscous results) are determined with post-processing analysis tools (the Eppler code, Mark Drela's XFOIL, other codes, and finally when things look promising the wind tunnel). 事实上,机翼性能特点(粘性成绩)决意与后处理分析工具(空泡典马克drela的xfoil,其他代码,最后看东西时许诺的风洞). The Eppler code, XFOIL, the wind tunnel, etc must be separately obtained to complete the design-tool suite. 在空泡典xfoil、风洞等必须分开取得完成设计工具套房. If you develop a promising design, need some wind tunnel time and are associated with a potential sponsor, we might be able to help. 如果你设计一个很有发展,需要一些时间和风洞涉及潜在赞助我们也许能够帮忙. The method has been used to design a series of low speed airfoils, many of which have been successfully applied as listed below. 该方法已用于设计一系列的低速翼型,其中许多项目已成功应用于列如下. To put the method in some perspective, it helpful to briefly outline the two general approaches to airfoil design. 把一些观点方法,它有助于扼要介绍两个一般方式翼型设计. There are "direct" and "inverse" methods. 有"直接"和"反"法. Direct methods are based on the design-by-analysis approach in which the airfoil shape is specified first. 直接的方法是基于设计逐案分析的方法是机翼形状指定第一. The given airfoil is then analyzed to determine, say, its velocity distribution. 由于机翼的分析,以确定那是说,它的速度分布. The airfoil shape is then adjusted until the desired velocity distribution is obtained. 然后是调整翼型的形状,直到取得预期的速度分布.  One difficulty with direct methods is that the designer spends a great deal of time focusing on the velocity distribution; the geometry is secondary. 一个直接的方法就是难度设计者花费大量的时间专注于速度分布;几何为辅. Thus, it would be more advantageous to specify the velocity distribution from the outset and from that determine the airfoil shape. 因此,它会更有利,指明速度分布,从一开始就确定,从机翼形状. Such methods are called inverse methods. 这种方法被称为逆方法.  PROFOIL-WWW is based on an inverse method as described. profoil-逆法是基于WWW的描述. The velocity distribution is specified by a limited number of parameters. 指定的速度分布是有限的参数. In fact, at a minimum only 8 parameters are needed to define the entire velocity distribution (see screen grab below). 事实上,至少8只需要确定参数全部速度分布(见屏幕下面抓斗). In the method, such an airfoil is termed a four-segment airfoil. 在方法,这种称为翼型四个部分机翼. Of course, for more complex airfoils (more practical designs) more parameters are needed. 当然,对于较复杂的翼型(更为实用设计)需要更多的参数. But one advantage of the method is that the entire velocity distribution about the airfoil does not have to be described point-by-point, which could be quite tedious, depending on how it is implemented. 该方法的优点之一是,整个翼型的速度分布不须形容逐点、可相当繁琐,取决于它是如何落实.  The method has it roots in a branch of mathematics called conformal mapping. 该方法的数学分支,它植根于所谓形映射. Without going into any details, it is only necessary to know that the airfoil is generated from a circle that is "mapped" into an airfoil as depicted in the figure above. 刻下任何细节只是要知道,机翼是产生了一圈即"描绘"描绘成翼型的数字以上. The Joukowski airfoil problem is the simplest application of conformal mapping to airfoil design. joukowski问题是最简单的翼型形映射应用到机翼设计. The mathematical transformation is fixed and the airfoil is moved to generate different airfoil geometries. 数学变换是固定机翼的翼型几何移到产生不同. An alternative approach is to fix the geometry and change the transformation to get different airfoils. 另一种方法是把几何学得到改造,改变翼型不同. This strategy is used in the current approach. 这种策略是用现有的模式. The transformation, however, is not changed explicitly by the designer, but instead determined from the parameters that define the velocity distribution. 改造,但并未改变明确的设计师而是取决于从参数确定速度分布. Thus, conformal mapping is merely used as a bridge to allow the designer to specify the velocity distribution. 因此,形映射只是作为桥梁,让设计师指明速度分布. The details of the method are for the most part transparent to the user. 详细方法是最透明的部分用户. Another aspect of the method is that "multipoint" design can be performed. 另一个办法是,"多点"的设计,可以进行. The velocity distributions previously shown were for a single angle of attack. 先前的速度分布列分别为单一迎角. When the velocity distribution is specified for a single condition it is refered to as "single point" design. 当速度分布是一个特定条件是被称为"单点"的设计. Typically, however, good performance is required over a range of angles of attack, say, two different angles of attack. 通常,但需表现良好射程超过迎角,例如两个不同的角度攻击. For example, high-lift (low speed/high angle of attack) performance may be required as well as low-lift (high speed/low angle of attack). 例如高扬程(低速/高攻角)表现以及可能需要低扬程(高速/低迎角). The process of prescribing the velocity at two (or more conditions) is referred to as "multipoint" design. 9.9进程的速度在两个(或两个以上条件)称为"多点"的设计. PROFOIL has a multipoint design capability. profoil多有设计能力. For instance, the velocity distribution can be prescribed for the upper surface at a high angle of attack while simultaneously the velocity distribution can be prescribed for the lower surface at a low angle of attack. 比如可指定的速度分布在水面上的高攻角的同时,可以在指定的速度分布在低角度下地面攻击. This multipoint design feature will be discussed in more detail in the examples. 这一设计特点多则会更详细的例子. PROFOIL-WWW is setup to allow web users to design airfoils using the html forms support. profoil--WWW的格局是让网民使用的翼型设计的HTML形式的支持. The parameters are specified and submitted. 参数指定并提交. Calculations are performed on the server and the associated figures and results are written to html files on the fly and displayed. 计算演出的服务器及相关人物和成果撰写的HTML档案的飞行及结果. The tutorial begins with a simple four-segment airfoil. 补习始于一个简单的四部分机翼. The various design parameters are introduced before moving on to a six-segment airfoil. 各设计参数介绍转学至六部分机翼. Finally, a special form allows the user to prescribe any number of segments so that practical airfoils can be designed. 最后,一种特殊形式允许用户指定任何数目的片段,可以使实际翼型设计. In this regard, several airfoil templates are given based on existing designs, eg, the SD7037 airfoil and others. 在这方面,有几个版本,基于现有翼型设计,例如,sd7037翼型等. The Web version of the code allows for the prescription of the inviscid velocity distribution about the airfoil. 网上版的代码允许处方粘速度分布的翼型. The full-featured version of the code has additional capabilities that are not available on the Web. 全版的内容,实务能力也没有提供额外的网站. In particular, a boundary-layer method is included to permit the specification of boundary-layer developments. 尤其是边界层方法包括允许指定边界层的发展. For instance, the development of the boundary-layer shape parameter can be prescribed on the upper surface to allow for maximum lift or extended runs of laminar flow, depending on the design requirements. 比如开发了边界层的形状参数,可以指定允许的最高表面上取消或延期举办层流、视乎设计要求. The method also permits inverse design with flaps, specification of geometric constraints (thickness, camber, etc.). 办法还允许逆向设计皮瓣、几何约束规格(厚度、拱等). More details of the method can be found in the references below. 更详细的方法可以找到述如下. | 
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发表于 2006-12-31 22:45
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Also, check out Mike Garton's new airfoil-performance comparison page at 
