From f216c342edea0113c151ce076d873ce590ccb886 Mon Sep 17 00:00:00 2001
From: David Dorchies <david.dorchies@inrae.fr>
Date: Mon, 17 Apr 2023 12:57:14 +0000
Subject: [PATCH] feat(MacroRugo): implementation of Ferguson equation
Refs #346
---
src/macrorugo/macrorugo.ts | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/src/macrorugo/macrorugo.ts b/src/macrorugo/macrorugo.ts
index ef723740..2d021d83 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)
}
}
--
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