Domain: Engineering — Aerospace Engineering
Target concept: The flow attaches better after the flap is deployed, delaying stall and moving the flow separation point backward.

Video generation prompt: In the wind tunnel, the wing model with flaps is placed in a steady airflow, and the smoke flow changes are observed before and after the flaps are deployed.

Evaluation guide:
(i) Target concept: Delayed boundary layer separation via increased camber from flap deployment.
Minimum mechanism: Steady laminar/smoke flow must be present; flaps must be physically deployable and alter wing geometry; separation point must be visually inferable from smoke trajectory discontinuity.
(ii)Storyline: [Frame 0–t1] Wing with flaps retracted → smoke flows over upper surface and separates early (visible kink/break in streamline near leading edge). [t1] Flap deployment action occurs (flap rotates downward, no repositioning of wing). [t1+1–end] Smoke now remains attached longer, with separation point appearing farther aft (kink/break relocated toward trailing edge); no reversal or upstream reattachment. Entire sequence viewed from fixed frontal/side oblique angle showing full wing span and upper surface; smoke source remains constant; lighting uniform; no occlusion of separation region.

Manual:
Experimental Procedure
1. Place wing model with deployable flaps in wind tunnel test section.
2. Introduce steady smoke stream upstream of wing.
3. Record smoke flow over wing surface before flap deployment.
4. Deploy flaps fully.
5. Record smoke flow over wing surface after deployment.
Observation of Experimental Phenomena
Before flap deployment: smoke flow separates early near wing leading edge; turbulent wake appears close to leading edge.
After flap deployment: smoke flow remains attached farther downstream; separation point visibly shifts backward along upper surface; wake appears delayed and narrower.
Summary of Experimental Principles
Flap deployment increases effective camber and delays boundary layer separation, moving the flow separation point backward and increasing lift before stall.

Prompt Grounding rubric:
level_1: No wing model visible; no flap deployment action shown; no smoke flow visualization; no wind tunnel context present.
level_2: Wing model is present but lacks identifiable flaps; smoke is visible but not associated with airflow over wing; no before/after flap deployment sequence shown.
level_3: Wing model with flaps is present in a wind tunnel setting; smoke flow is visible over the wing; flap deployment action occurs once, but no clear temporal separation between pre-deployment and post-deployment smoke behavior is shown.
level_4: Wing model with flaps is present and clearly identifiable; smoke flow is continuously visible over the wing surface; flap deployment action is shown once, and two distinct smoke flow states are visually separated in time (one before deployment, one after), with same viewpoint and no object replacement.
level_5: Wing model with flaps is present and correctly proportioned; smoke flow is continuously visible over the wing surface throughout; flap deployment action is shown once, and two temporally sequential, non-overlapping smoke flow states are shown: first state (pre-deployment) ends before second state (post-deployment) begins, both observed from fixed viewpoint with identical framing, lighting, and background.

Scientific and Causal Correctness rubric:
level_1: Smoke flow shows no change across time; or flow separation point moves forward after flap deployment; or smoke detaches earlier post-deployment, contradicting stall delay principle.
level_2: Smoke flow appears continuous but shows no discernible shift in separation point; or separation point shifts inconsistently (e.g., backward then forward); or smoke behaves identically before/after despite flap motion.
level_3: Smoke flow shows a visible backward shift of the flow separation point after flap deployment; however, the shift occurs without clear temporal linkage to the flap deployment action, or separation point location is ambiguous due to low contrast or occlusion.
level_4: Smoke flow shows a clear backward shift of the flow separation point after flap deployment; the shift is unambiguous and persists for the duration of the post-deployment phase; no contradictory forward movement or reattachment upstream observed.
level_5: Smoke flow shows a clear, sustained backward shift of the flow separation point immediately following flap deployment; the separation point remains stably located farther downstream in the post-deployment phase compared to the pre-deployment phase; no transient reversal, flickering, or inconsistent detachment behavior occurs.

Spatiotemporal Consistency rubric:
level_1: Wing model teleports or changes position/orientation between frames; smoke flow discontinuously appears/disappears or jumps spatially; lighting or shadow abruptly changes mid-sequence; structural break in wing or flap geometry observed.
level_2: Wing model remains in place but exhibits visible jitter or scaling fluctuation; smoke flow has abrupt gaps or frame-to-frame discontinuity in trajectory; minor lighting flicker or localized shadow shift occurs.
level_3: Wing model remains fixed in position and orientation; smoke flow is continuous in appearance but exhibits minor localized warping or brief opacity inconsistency; lighting and shadows remain consistent overall with no abrupt changes.
level_4: Wing model remains fixed in position, orientation, and scale; smoke flow is fully continuous in trajectory and density across all frames; lighting, shadows, and background remain stable with no detectable variation.
level_5: Wing model remains fixed in position, orientation, scale, and surface texture; smoke flow is fully continuous in trajectory, density, and dispersion pattern; lighting, shadows, and background remain perfectly stable with zero detectable variation across all frames.