simulator.atterwind.info/windsheer.html at master · flyinggorilla/simulator.atterwind.info · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
<!DOCTYPE html>
<html lang="en">
<head>
    <title>calculate windsheer</title>
    <meta charset="utf-8">
</head>

<body>
    <div id="info">
        hello
    </div>

    <script>
        // https://websites.pmc.ucsc.edu/~jnoble/wind/extrap/
        let refheight = 10;
        let refspeed = 10;
        let evalspeed;
        let evalheight = 0.01;
        let roughness = 0.002;
        evalspeed = refspeed*(Math.log(evalheight/roughness))/(Math.log(refheight/roughness));
        //console.log(evalspeed);

        // https://en.wikipedia.org/wiki/Wind_gradient
        let speed10 = 10;
        let height10 = 10;
        evalspeed;
        evalheight = 0.01;
        let hellman = 0.27; // alpha
        evalspeed = speed10*(Math.pow((evalheight/height10), hellman));
        //console.log(evalspeed);

        // location	α
        // Unstable air above open water surface:	0.06
        // Neutral air above open water surface:	0.10
        // Unstable air above flat open coast:	0.11
        // Neutral air above flat open coast:	0.16
        // Stable air above open water surface:	0.27
        // Unstable air above human inhabited areas:	0.27
        // Neutral air above human inhabited areas:	0.34
        // Stable air above flat open coast:	0.40
        // Stable air above human inhabited areas:	0.60


        // https://en.wikipedia.org/wiki/Apparent_wind
        function apparentWind(sog, cog, tws, twd) {
            let twa = twd-cog;
            /*if (twa < 0) {
                twa = 360 + twa;
            }*/
            let A = Math.cos((twa*Math.PI/180));
            let aws = Math.sqrt((tws*tws)+(sog*sog)+(2*tws*sog*A));
            let B = Math.cos(twa*Math.PI/180);
            let C = (((tws*B)+sog)/aws);
            let D = Math.acos(C);
            let awa = twa <= 0 || twa > 180 ? - D*180/Math.PI :  D*180/Math.PI;
            let awd = cog + awa;

            let awastr = "";
            if (twa < 0 || twa > 180) {                // Wind from Port
                let awa1 = 360 - awa.toFixed(0);
                awastr = "-" + awa.toFixed(0) + " (" + awa1 + ")";
            } else {
                awastr = awa.toFixed(0);
            }
            //console.log("apparrent wind: " + awastr);
            console.log("sog: " + sog + " cog: " + cog + " aws: " + aws.toFixed(1) + " awa: " + awa.toFixed(1) + " awd: " + awd.toFixed(1));

            return { aws: aws, awa: awa, awd: awd};

        }

        apparentWind(10, 90, 0, 0);   // awa: 0, awd: 90
        apparentWind(10, -90, 0, 0);  // awa: 0, awd: -90
        apparentWind(0, 60, 10, 0);   // awa: -60, awd: 0
        apparentWind(0, -60, 10, 0);  // awa: 60, awd: 0
        apparentWind(0, 90, 10, 0);   // awa: -90, awd: 0
        apparentWind(0, -90, 10, 0);  // awa: 90, awd: 0
        apparentWind(5, 90, 10, 0);   // awa: -60, awd: ~30
        apparentWind(5, -90, 10, 0);
        apparentWind(10, 90, 10, 0);
        apparentWind(10, -90, 10, 0);
        apparentWind(15, -90, 10, 0);
        apparentWind(15, 90, 10, 0);
        apparentWind(10, 180, 10, 0);
        apparentWind(10, -180, 10, 0);
        apparentWind(5, 180, 10, 0);
        apparentWind(5, -180, 10, 0);
        apparentWind(10, 135, 10, 0);
        apparentWind(10, -135, 10, 0);
        apparentWind(10, 45, 10, 0);
        apparentWind(10, -45, 10, 0);


</script>
</body>

</html>