PSE Hydraulic Responses

PSE Hydraulic Responses

A Protective System Element (PSE) is a 1-D cross-section of a coastal structure. For every storm (PROS replicate, LCS storm or DET storm), CHESS computes the structure's hydraulic responses from the forcing at the toe: still water level (SWL), significant wave height (Hm0) and peak period (Tp). The dispatcher is compute_structure_response.m; each response has its own config.compute_* switch, and the structure type decides which responses apply.

Which responses apply to which structure

Response	Levee (1)	Floodwall (2)	Rubble mound (3)	Low-crested breakwater (4)
EurOtop Wave Runup R2p	✓		✓	✓
EurOtop Overtopping Discharge q	✓	✓	✓	✓
EurOtop Overtopping Discharge Volume Q vol (Timeseries)	✓	✓	✓	✓
EurOtop Wave Transmission Kt	✓	✓	✓	✓
Goda Vertical Wall Pressures P1 P2 P3 Pu		✓
Floodwall Nappe Flow Response		✓
Melby Seaside Armor Stone Stability Dn50			✓
Van Gent Leeside Armor Stone Stability Dn50			✓
Submerged Armor Stone Stability Dn50			✓
Melby Low Crested Breakwater Stability				✓
Damaging Depth	✓	✓	✓	✓
Seaside Armor Damage Progression LCS CSR (LCS)			✓
Leeside Armor Damage Progression LCS CSR (LCS)			✓

Switches that do not apply to a structure type are turned off by compute_structure_response.m. Two switches pull in another response: compute_nappe forces compute_q, and compute_p2_p3 forces compute_p1.

Responses by physical process

Run-up and overtopping

How high waves run up the face and how much water passes the crest.

• EurOtop Wave Runup R2p: run-up exceeded by 2% of waves.
• EurOtop Overtopping Discharge q: mean overtopping rate, including weir overflow when the crest is submerged.
• EurOtop Overtopping Discharge Volume Q vol: overtopping volume over the storm hydrograph.
• Overtopping Damage Classification: what a given q means for vehicles, people, buildings and structures (CEM Table VI-5-6).
• Helpers used by the leeside armor equations: Wave Runup Exceedance z1p, Crest Velocity Exceedance u1p.

Transmission

How much wave energy passes over or through the structure.

• EurOtop Wave Transmission Kt.

Wall loads

Forces on and behind vertical walls.

• Goda Vertical Wall Pressures P1 P2 P3 Pu: wave pressures on the wall face and uplift.
• Floodwall Nappe Flow Response: where the overtopping jet lands behind the wall and how hard it hits.

Armor stability

Stone size needed for a target damage level, or stability of an existing armor layer.

• Melby Seaside Armor Stone Stability Dn50: seaside armor (momentum flux).
• Van Gent Leeside Armor Stone Stability Dn50: rear-side armor under overtopping.
• Submerged Armor Stone Stability Dn50: correction when the crest is submerged.
• Melby Low Crested Breakwater Stability: low-crested breakwaters (Dn50 in PROS, stability factor in LCS).

Damage progression (LCS)

Cumulative armor damage over a life cycle for an existing stone size.

• Seaside Armor Damage Progression LCS CSR.
• Leeside Armor Damage Progression LCS CSR.

Hazard metrics

Site hazards independent of the structure geometry.

• Damaging Depth: water column from the offshore bed to the controlling wave crest.

Before reading an equation page

• Elevations are signed and slopes are entered as cot(α) (Model Conventions).
• A dry toe (h < 0) or a storm without waves gives NaN for wave-driven responses (except Kt, which is 0), while surge-only responses are still computed.
• Shared symbols, influence factors and wave-period conversions are on Structure Response Equations.