分类： Mechanical Engineering – 机械

(English version follows Chinese Part)

其实这个就是之前谈过的莫迪图查询器， 但是后来因为学习上比较忙，就没怎么研究。这两天看了一下，似乎并不需要做莫迪图查询器这么复杂，只需要根据输入参数代入逼近公式运算就可以得到所求摩擦系数。具体需要利用JavaScript来实现，通过输入的参数，在服务器端按照逼近公式计算，显示运算结果。

Actually, it is the moody chart checker I have mentioned before, but I was too busy for my courses to think about how to develop the checker. In these few days I found that there is no need to build a chart checker, a web calculator will work. Input necessary values and calculate with equation approximation, the display the result on the page. JavaScript will be used to develop the calculator.

按照Darcy friction factor formulae中提供了很多种逼近公式。

Darcy friction factor formulae shows many equation approximations.

首先尝试了一下Alashkar公式。

Try the Alashkar equation.

运算部分的JS中代码大概如下：

Calculation part of the JS code:

[code language=”javascript”]

function cal(form)
{
var a=Number(form.a.value);
var b=Number(form.b.value);
var c=Number(form.c.value);
var d=a/(b*3.7065);
var e=2.5226/c;
var f=1.665368035*e;
var g=Math.pow(f,0.8373492157);
var h=d+g;
var i=Math.log(h);
var j=e*i;
var k=0.8784893582*j;
var l=d-k;
var m=Math.log(l);
var n=e*m;
var o=0.8686068432*n;
var p=d-o;
var q=Math.pow(o,-2);
var r=Math.log(q);
form.s.value = 1.325474505*r;
}

[/code]

然而求出来的结果似乎并不对。还需要再研究研究。

It works but the result is strange, more research to do.

(English version follows Chinese Part)

这个学期在上空气动力学这门课，其中很多计算涉及到查询莫迪图。我在想能不能弄个网页版的莫迪图查询器帮助提高效率。具体实现方法可能要参考公差查询器，用excel数据表来记录离散的莫迪图线的值，或者更加复杂的方法。先在这里提出一个设想。

I have a course this semester, which is aerodynamics. Large parts of calculations are based on checking moody chart. I am considering about set up a web-base checker to assist my calculating efficiently.  Maybe similar method from tolerance checker is applied. Discrete points of moody chart recorded in excel and read by php. Or more complicated. Mark here.