{
  "annotation_id": "59b93fee-6db1-4340-b93d-e371915aa579",
  "date_created": "2026-03-02T18:00:50.182000Z",
  "date_modified": "2026-03-02T18:00:50.182000Z",
  "file_hash": "08357ce4f15334f5c22ce0d47e1a7b1050764c691d8934d920a93efb18223357",
  "private": false,
  "record": {
    "abstract": "Aerodynamic force generation and mechanical power requirements of a dragonfly\n(Aeschna juncea) in hovering flight are studied. The method of numerically\nsolving the Navier-Stokes equations in moving overset grids is used.\n  There are two large vertical force peaks in one flapping cycle. One is in the\nfirst half of the cycle, which is mainly due to the hindwings in their\ndownstroke; the other is in the second half of the cycle, which is mainly due\nto the forewings in their downstroke. Hovering with a large stroke plane angle,\nthe dragonfly uses drag as a major source for its weight supporting force\n(approximately 65% of the total vertical force is contributed by the drag and\n35% by the lift of the wings). The vertical force coefficient of a wing is\ntwice as large as the quasi-steady value. The interaction between the fore- and\nhindwings is not very strong and is detrimental to the vertical force\ngeneration. Compared with the case of a single wing in the same motion, the\ninteraction effect reduces the vertical forces on the fore- and hindwings by\n14% and 16% of that of the corresponding single wing, respectively. The large\nvertical force is due to the unsteady flow effects. The mechanism of the\nunsteady force is that in each downstroke of the hindwing or the forewing, a\nnew vortex ring containing downward momentum is generated, giving an upward\nforce. The body-mass-specific power is 37 W kg-1, which is mainly contributed\nby the aerodynamic power.",
    "arxiv_id": "physics/0404041",
    "authors": [
      "Mao Sun",
      "Shi Long Lan"
    ],
    "categories": [
      "physics.flu-dyn",
      "physics.bio-ph"
    ],
    "title": "A computational study of the aerodynamic forces and power requirements   of dragonfly Aeschna juncea hovering",
    "url": "https://arxiv.org/abs/physics/0404041"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "a14e41e1-a4ec-41d8-9f81-93de08a4e57e",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}