| 摘要 |
<p>A wingsail has two rigid symmetrical aerofoil section sail sections (10, 12) which are mounted one downstream of the other, the trailing sail section (12) being freely pivotally mounted to the center line of the leading sail section (10) so that its leading edge just clears the trailing edge of leading sail section. A hinged symmetrical rigid flap (14) extends downwind from the trailing edge of the leading sail section (10), the flap being adapted to be moved to one side or the other in response to a swinging movement of the trailing sail section (12) relative to the leading sail section (10) so that the leeward surface of the flap (14) can form a more or less smooth extension of the leeward surface of the leading sail section (10), the spacing between the flap (14) and the trailing sail section (12) forming a convergent linear nozzle so as to assist in directing air over the leeward surface of the trailing sail section (12) and energize the local flow, prolong the extent of attachment of flow and enable the optimum thrust coefficient to be reached.</p> |
