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Reflected overpressure (normal reflection)

Peak reflected overpressure on a rigid surface facing the blast, from the incident (side-on) overpressure.

Civil-protection / accidental-explosion scope only (UFC 3-340-02, public release). Weapon-effects and penetration calculations are out of scope.

Ideal-gas 0° (normal) reflection (Rankine-Hugoniot). Cr ranges 2 (weak shock) to 8 (strong-shock ideal-gas limit). Oblique incidence and real-gas effects differ (UFC 3-340-02 Fig. 2-193).

Inputs

From the peak-overpressure tool (free-field ΔP).

Results

Reflection coefficient Cr—
Reflected overpressure Pr— kPa
Pr [bar]—

Citations

R-HPr = 2·Pso·(7·P0+4·Pso)/(7·P0+Pso). Rankine-Hugoniot normal reflection (Smith & Hetherington 1994).
VERIFYCross-checked vs independent implementation: Pso=35 → Cr=2.28, Pr=79.88 kPa; Pso=70 → 177.73 kPa.

Engine: blast.js v0.1.0 · Method: Rankine-Hugoniot · Date:

Peak-overpressure tool

Preliminary calculation tool. Results are for preliminary sizing and cross-check only. Final design, sealed responsibility, and permit submissions require the full official text of the referenced regulations and the review of a licensed engineer.