Hydrodynamic Veil

A kinematic model of how a guide boom, bubble curtain and crossflow jets steer Blue Blubber jellyfish away from a breakwater cooling-water intake. Barakah-scale flows, generic geometry.

Team Simer · ENEC challenge, ATP 2026
Q = 280 m³/s · depth 10 m
boom draft 2 m · plan view, metres

Iteration 1 pinned jellyfish against the boom where suction is strongest; iteration 2 moves the boom about 90 m out.

Bypass
0%
0 jellyfish
Pocket
0%
0 jellyfish
Intake
0%
0 jellyfish
Sim clock
00:00:00
0 in view
Power draw
0 kW
team estimate

Share of resolved jellyfish. Counts restart when you change the setup.

Top 2 m Below 2 m Active Idle Bypass Pocket Intake

Model assumptions

A quick surrogate for exploring layouts. The SimScale CFD study uses the same geometry and is the reference for flow detail.

  • Kinematic surrogate, not CFD. Velocities are superposed: uniform tide, a radial intake sink Q/(H·π·r) toward the mouth (r ≥ 15 m), the jet plumes and the curtain outflow. No momentum exchange, no turbulence model.
  • Two layers. Top 2 m (above the boom draft) and 2–10 m. The boom is a wall for the top layer only; deep water and animals pass under it.
  • Jellyfish are weak swimmers. Each swims at a fixed speed with a slowly wandering heading (0.3 rad/√min) and is otherwise carried by the flow. They do not avoid bubbles or structures.
  • Boom leakage. An animal pressed against the boom is pulled under with probability max(0, vn − vcrit)·Δt / 10 per 2 s step, where vn is the velocity into the boom face and vcrit the skirt escape velocity (default 0.15 m/s).
  • Bubble curtain. Surface outflow of 0.25·e−d/10 m/s away from each firing segment, on both sides. Deep animals passing within 3 m of it are lifted to the top layer with plift = 0.6, once per crossing. Iteration 2: diffuser laid directly beneath the boom line (offset 0 m), so at the outer boom face the outflow points seaward and opposes the incoming water. Iteration 1: 6 m seaward of the boom, where the outflow between curtain and boom pushes animals into it.
  • Tide-aware control (iteration 2). The curtain fires on the upstream leg and the offshore leg; the downstream leg is off. Only the upstream jet bank fires. Iteration 1 has one curtain line and one jet bank.
  • Jets. Banks of three 2 m nozzles at 2.0 m/s, plane-jet plume: centreline Uc = min(U0, 2.4·U0·√(b0/s))·e−s/60, half-width b0/2 + 0.1·s. The e−s/60 factor makes plumes die out within 100–150 m, a conservative stand-in for bending by the tide. Plumes add linearly.
  • Pocket. Catches 90% of top-layer animals that reach the mouth. Deep animals and the rest are counted as intake.
  • Bypass means leaving the model domain, or still drifting offshore after 4 h.