| 摘要 |
Hydrodynamic duct mounted at the bow of a vessel, comprising a horizontal wall portion (1) and two lateral wall portions (2,3), whereby the flow through the duct acquires substantially different characteristics from the flow outside it and thereby wave making and frictional resistances are reduced and the fuel conventionally required for the propulsion of the vessel is reduced accordingly. The duct is arranged with the Center of Low Pressure (1c) corresponding to a zero angle of attack onto the horizontal wall portion (1) being located in the region of generation of the first bow wave and with the Centers of Low Pressure (2c,3c) of the lateral wall portions (2,3) in the region of connection thereof with the horizontal wall portion (1) being located in a selected position between the Center of Low Pressure (1c) and up to or slightly forwardly the leading edge (1a) of the horizontal wall portion (1). |
| 主权项 |
1. Hydrodynamic duct mounted at the bow of a vessel in a position such that it may under any circumstances be immersed in water underneath the sea surface, said duct producing an effect of reduction of wave making and frictional resistances encountered during propulsion of the vessel, comprising a horizontal wall portion (1) having a section (al) of a specific geometrical shape with a length (¾) in the direction of flow and a thickness (at), said horizontal wall portion (1) extending on either side of the bow line with an internal surface (10) within the duct and an external surface (11) outside of the duct and a pair of lateral wall portions (2, 3) of section (b) of a specific geometrical shape with a length (bl) in the direction of flow and a thickness (bt), said lateral wall portions (2, 3) being connected to said horizontal wall portion (1) and extending upwardly on either side of the bow thereby forming together with said horizontal wall portion (1) and with the surfaces of the bow sides to which they are connected by means of supporting pillars (4) a region within the duct wherein the flow is substantially differentiated from the flow of water outside of the duct, such differentiation resulting in the improvement of cruising characteristics of the vessel, said lateral wall portions (2, 3) having internal surfaces (20, 30) within the duct and external surfaces (21, 31) outside of the duct, wherein the hydrodynamic duct is characterized in that the section (a) of said horizontal wall portion (1) and the section (b) of said lateral wall portions (2, 3) are being arranged with their leading edges (1a) and (2a, 3a) respectively at the frontal ends thereof wherein flow enters the duct and their trailing edges (1b) and (2b, 3b) respectively at the rear ends thereof wherein flow exits the duct, wherein the position of the Center of Low Pressure (1c) located along the internal surface (10) of section (a) of the horizontal wall portion (1) is appropriately selected in correspondence with the angle of attack onto said horizontal wall portion (1) to lie in the region of generation of the first bow wave, along or marginally forwardly the bow line and wherein the position of the Centers of Low Pressure (2c, 3c) located along the internal surfaces (20, 30) of section (b) of the lateral wall portions (2, 3) in the region of connection of the lateral wall portions (2, 3) with the horizontal wall portion (1) is appropriately selected in correspondence with the angle of attack onto said lateral wall portions (2,3) to lie at a selected position in between the Center of Low Pressure (1c) and the leading edge (1a) of the horizontal wall portion (1) or projecting forwardly beyond the leading edge (1a), wherein the lateral wall portions (2, 3) are made at a suitable length so as to obtain coincidence of the trailing edges (2b, 3b) thereof with the trailing edge (1b) of the horizontal wall portion (1).
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