Domain: Engineering — Aerospace Engineering
Target concept: Delta wings generate leading-edge vortices at high angles of attack. Streamline visualization reveals the vortex structure, which helps maintain lift.

Video generation prompt: Place the triangular wing model in the wind tunnel test section under a steady airflow, inject smoke flow, and gradually increase the angle of attack.

Evaluation guide:
(i) Target concept: Leading-edge vortex generation on delta wing under increasing angle of attack.
Minimum mechanism: Steady airflow must be present; smoke must act as passive tracer; wing geometry must be triangular/delta planform; angle increase must be about pitch axis; vortex formation requires sufficient angle to induce flow separation at leading edge.
(ii)Storyline: Frame 1–2: Wing stationary at low angle, smoke flowing straight. Frame 3–4: Wing begins rotating upward (pitch-up). Frame 5–6: Wing stabilized at medium angle; smoke starts curving near leading edge. Frame 7–8: Wing stabilized at high angle; two coherent, rotating smoke vortices fully formed and sustained downstream. All events occur from fixed frontal/slightly oblique viewpoint showing full wing span, leading edge, and downstream smoke path; no cuts or viewpoint shifts.

Manual:
Experimental Procedure
1. Place triangular wing model centered in wind tunnel test section.
2. Initiate steady airflow.
3. Inject smoke flow at wing leading edge.
4. Gradually increase wing angle of attack while observing smoke.
Observation of Experimental Phenomena
At low angle: smoke flows smoothly over wing surface. At high angle: paired, rotating, stable vortices emerge from leading edge and extend downstream.
Summary of Experimental Principles
Delta wings generate leading-edge vortices at high angles of attack. Streamline visualization reveals the vortex structure, which helps maintain lift.

Prompt Grounding rubric:
level_1: No triangular (delta) wing model is shown, no wind tunnel test section is visible, no smoke is injected, or the wing's angle of attack never appears to change; none of the prompt's required elements are established.
level_2: The triangular wing model appears, but not clearly inside a wind tunnel test section; smoke is absent or appears somewhere unrelated to the wing; the wing's orientation looks the same throughout with no visible change in pitch.
level_3: The triangular wing model sits inside a wind tunnel test section, smoke is visibly injected near the wing's leading edge, and the wing is shown at some angle relative to the airflow, but only a single, unchanging angle is shown, with no visible increase over the sequence.
level_4: The triangular wing model sits inside the test section, smoke is injected continuously near the leading edge, and the wing is shown pitching to at least two distinct, visibly different angles in order (e.g., a lower angle followed by a noticeably higher one).
level_5: The triangular wing model stays centered inside a clearly bounded test section, smoke is injected continuously near the leading edge for the whole sequence, and the wing pitches through three or more increasing angles in strict order (low, then medium, then high), with each angle held long enough for the smoke pattern to settle before the next pitch change; the wing's only motion is this controlled rotation about its pitch axis.

Scientific and Causal Correctness rubric:
level_1: The smoke shows no vortex-like structure at any angle; it flows in a uniform, straight pattern regardless of how the wing is pitched.
level_2: The smoke passes the wing without any visible deviation from a straight, laminar pattern even at the highest angle shown; no localized swirling, thinning, or thickening near the leading edge appears.
level_3: At the higher angle(s) of attack, the smoke develops a localized curl or mild spiral near the leading edge, but no continuous, well-defined rotating column forms, and the smoke pattern at the low angle looks essentially the same as at the high angle.
level_4: At the higher angle(s) of attack, the smoke forms a continuous, coherent, rotating column that originates at the leading edge and stretches downstream; this rotating column is absent or clearly weaker at the lower angle(s), so the contrast between low- and high-angle behavior is visible within the sequence.
level_5: At the low angle, the smoke stays smooth and straight over the wing with no rotation; as the angle increases, a pair of symmetric, tightly-coiled vortices forms at both wingtips and stays coherent downstream; the vortices visibly tighten and strengthen as the angle increases, with no unrelated turbulence or eddies appearing elsewhere on the wing.

Spatiotemporal Consistency rubric:
level_1: The wing's angle or position changes abruptly between frames with no rotation motion connecting the two states, as if two separate shots were spliced together; the smoke stream is fully present in one frame and completely absent in the one before it with no fade-in; the test-section walls appear solid in one frame and become see-through or missing in the next; or the lighting swings abruptly between bright and dark between frames with no visible cause.
level_2: The wing's pitch jumps between two orientations without passing through the angles in between; the smoke flow flickers off and on for a frame or reverses direction momentarily; the test-section boundary appears to shift relative to the wing without any camera movement to explain it; or the shadows cast by the wing or wind-tunnel structure swing to a different angle or vanish even though the lighting appears unchanged.
level_3: The wing rotates smoothly about a single, fixed pivot point as its angle increases; the smoke flows without interruption or reversal throughout; the test-section walls stay in the same position relative to the wing in every frame; the lighting stays consistent in direction and intensity throughout, with no unexplained brightening, dimming, or shadow shift; nothing in the frame clips through another object or floats free of its expected position.
level_4: All conditions for score 3 are met, and additionally: the smoke's density and opacity stay visually consistent as the angle changes, apart from the vortex formation itself; the wing's rotation and the smoke's response to it stay in step, with no frame where the wing has already pitched up but the smoke still looks like the lower-angle pattern; the camera framing does not shift or distort during pitch changes.
level_5: All conditions for score 4 are met, and additionally: the wing's rotation traces a single smooth arc with no stutter or reversal; the smoke's origin point at the leading edge stays fixed throughout; the test-section walls, floor, and ceiling keep a rigid, unbroken shape across the whole sequence; the motion of the smoke and wing together looks fluid frame to frame, with no frame showing a frozen or duplicated image.