forked from 1b-agent/opencadstudio-upstream
Michael FlynnandClaude Opus 4.8
9b44eb6400
Adds a "Storm Sewer" ribbon tab backed by a new in-repo `stormsewer` engine crate (vendored under crates/). The engine implements standard public-domain methods — Rational-method peak-flow accumulation, Manning circular-pipe hydraulics, time-of-concentration / IDF intensity, and an HGL backwater pass with junction losses — with 24 unit tests and no external dependencies. Module (src/modules/storm_sewer/): - Drafting: SS_INLET / SS_JUNCTION / SS_OUTFALL place structure markers and SS_PIPE chains pipe runs (interactive CadCommands). - Analysis: SS_ANALYZE / SS_REPORT / SS_PROFILE open a .ssn network file, run the engine, draw the plan and HGL long-section, and print a report. - SVG icons; SS_* commands registered for command-line autocomplete. Integration is additive: build.rs auto-discovers the module and one dispatch block is added to src/app/commands.rs. 7 module integration tests. See src/modules/storm_sewer/INTEGRATION.md for the design and the optional follow-up (drive analysis from canvas geometry via XDATA). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
54 lines
1.4 KiB
Rust
54 lines
1.4 KiB
Rust
// SPDX-License-Identifier: GPL-3.0-or-later
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//! Rainfall intensity–duration–frequency (IDF) curves.
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//!
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//! Uses the common three-parameter form
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//!
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//! ```text
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//! i = a / (t + b)^c (i in in/hr, t in minutes)
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//! ```
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//!
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//! which fits NOAA Atlas-14 partial-duration data well over the 5–180 min
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//! range used in storm-sewer design.
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/// A three-parameter IDF curve for a single return period.
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#[derive(Clone, Copy, Debug, PartialEq)]
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pub struct IdfCurve {
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pub a: f64,
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pub b: f64,
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pub c: f64,
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}
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impl IdfCurve {
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pub fn new(a: f64, b: f64, c: f64) -> Self {
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Self { a, b, c }
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}
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/// Rainfall intensity (in/hr) for a storm duration `t_min` (minutes).
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pub fn intensity(&self, t_min: f64) -> f64 {
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let t = t_min.max(0.0);
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self.a / (t + self.b).powf(self.c)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn intensity_decreases_with_duration() {
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let idf = IdfCurve::new(120.0, 10.0, 0.8);
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let short = idf.intensity(5.0);
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let long = idf.intensity(60.0);
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assert!(short > long, "short {short} long {long}");
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assert!(long > 0.0);
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}
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#[test]
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fn intensity_known_value() {
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// a=120,b=10,c=0.8 ; t=15 -> 120 / 25^0.8 = 9.14 in/hr (hand calc).
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let idf = IdfCurve::new(120.0, 10.0, 0.8);
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assert!((idf.intensity(15.0) - 9.14).abs() < 0.05, "{}", idf.intensity(15.0));
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}
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}
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