解析式表示的航空翼型

Airfoil Representation with Analytical Functions

提出了一种用简单的解析式表示航空翼型的方法。它避免了离散数据点中间没有定义，翼型表示不唯一的情况。其光顺性好，特别有利于ＣＡＤ／ＣＡＭ技术的应用。

It is usually convenient for airfoil to be represented with numerical data of discrete points but good fairing is quite difficult to ensure with such discrete data. We can achieve C 2 fairing through airfoil representation with analytical functions. Our research led to a mathematical method which could give a unique representation of airfoil with special generalized superand paraellipse functions(eq.1). In eq.(1), m and n are the powers to which sin θ and cos θ are to be raised respectively. m and n , once determined with our method, can allow us to comprehend fully the feature of either upper or lower surface of airfoil. We now describe briefly how C 2 fairing is obtained. Usually upper or lower surface of airfoil requires several different curves when for example spline functions are used. With our method, which employs approximation by least squares, one function is enough for either upper or lower surface of airfoil. Thus C 2 fairing is obtained. The aerodynamic characteristics of the airfoil obtained as described above are the same as those of the original airfoil which use numerical data of discrete points.