diff --git a/src/macrorugo/macrorugo.ts b/src/macrorugo/macrorugo.ts index ef723740c8b6ed84c29c4526a275dff3d74ec1c2..2d021d836f5449286c381fd6437bb0b28ebffbb1 100644 --- a/src/macrorugo/macrorugo.ts +++ b/src/macrorugo/macrorugo.ts @@ -287,8 +287,11 @@ export class MacroRugo extends FishPass { const reynolds = this.U0 * this.prms.Y.v / MacroRugo.nu; return 0.3164 / 4. * Math.pow(reynolds, -0.25); } else { - // Equation (3) (Cassan et al., 2016) - return 2 / Math.pow(5.1 * Math.log10(Y / this.prms.Ks.v) + 6, 2); + // Ferguson equation proposed in Cassan et al. (2017) + const a1 = 6.5; + const a2 = 2.5; + const ks = this.prms.Ks.v; + return 2 / Math.pow(a1 * a2 * ((Y + ks) / ks) / Math.sqrt(a1 * a1 + a2 * a2 * Math.pow((Y + ks) / ks, 5 / 3)), 2) } }