This paper deals with two new species of the genus Dactylogyrus from marine fishes of Gobiidae. A new subjective synonym that is also a new record in China is concerned.1. Dactylogyrus qinzhouensis sp.nov. (Fig.1, a-b...This paper deals with two new species of the genus Dactylogyrus from marine fishes of Gobiidae. A new subjective synonym that is also a new record in China is concerned.1. Dactylogyrus qinzhouensis sp.nov. (Fig.1, a-b)Type-host: Glossogobius giuri Site: gills Type-locality and date: Qinzhou, Guangxi; May 7,1995 Type-specimens: Holotype no.GXqz1995050701; paratypes no.GXqz1995050702-3 About ten species of Dactylogyrus have been reported from fishes of Bobiidae in the world. This new species is similar to Dactylogyrus soni Gussev, 1995 (gobii Tripathi, renamed) which has the same species of host , but differs from the latter in the shape and size of hamuli, connective bar and copulatory organ. This species has a shorter hamuli (0.050-0.065 mm) and a longer point (0.020-0.022 mm), while the known species with a longer hamuli (0.095-0.102 mm) and a short point. The two laterals of the connective bar of this species are warped and with undulated wave, and the laterals of the connective bar of the known species become thickened and wide. The copulatory organ of the new species has a coiled tube of length 0.115-0.134 mm , the supporting apparatus which has a curve at the end is divided into two lobes at the base, while the length of copulatory tube of the old species is only 0.030 mm, and the supporting apparatus of the known species is also different. So, we regard this species as a new species in science and name it after its locality.2. Dactylogyrus microgobius sp.nov. (Fig. 2,a-b)Type-host: Microgobius gulosus, Microgobius sp.Site: gills Type-locality and date: Qisha, Guangxi; Sep.5,1995 Type-specimens: Holotype no.GXqsha1995090501; paratypes no.GXqsh1995090502; HNhk1998040301 This species is similar to Dactylogyrus gudaoensis Chen, 1982, but distinguishs from the latter in the shape and dimensions of hamuli, connective bar and copulatory organ. The length of the hamuli of this species is distinct smaller than the latter’s. The connective bar of the known species has two tubercules in the middle, while the bar is short and strong without tubercule in this species. The copulatory tube is nearly "S" shaped and the supporting apparatus "Y" shaped in known species and both the copulatory tube and the supporting apparatus are curved as "C" and with a deep fovea near the terminal in this speices. Therefore we regard this species as new and name it after its host. 3. Dactylogyrus bialatus Wu, Wang&Jiang, 1988 has been reported which has the characteristic of being well developed inner root, embryonic type hooklets, being two small knob-like projections in the middle of the connective bar ,and being a slight curved copulatory tube and divided, hook-shaped distal ends of the supporting apparatus etc.. All these important features along with the dimensions of this species (table 1) are nearly the same as that of Pseudodactylogyrus haze Ogawa, 1984. According to the 1961 ICZN, we think that Dactylogyrus bialatus is a subjective synonym of Pseudodactylogyrus haze Ogawa, 1984. Pseudodactylogyrus haze ( syn. D. bialatus) is first recorded in China and Synechogobius ommaturus is a new host of this species.展开更多
In the present study, a new approach is applied to the cavity prediction for two-dimensional （2D） hydrofoils by the potential based boundary element method （BEM）. The boundary element method is treated with the so...In the present study, a new approach is applied to the cavity prediction for two-dimensional （2D） hydrofoils by the potential based boundary element method （BEM）. The boundary element method is treated with the source and doublet distributions on the panel surface and cavity surface by usethe of the Dirichlet type boundary conditions. An iterative solution approach is used to determine the cavity shape on partially cavitating hydrofoils. In the case of a specified cavitation number and cavity length, the iterative solution method proceeds by addition or subtraction of a displacement thickness on the cavity surface of the hydrofoil. The appropriate cavity shape is obtained by the dynamic boundary condition of the cavity surface and the kinematic boundary condition of the whole foil surface including the cavity. For a given cavitation number the cavity length of the 2D hydrofoil is determined according to the minimum error criterion among different cavity lengths, which satisfies the dynamic boundary condition on the cavity surface. The NACA 16006, NACA 16012 and NACA 16015 hydrofoil sections are investigated for two angles of attack. The results are compared with other potential based boundary element codes, the PCPAN and a commercial CFD code （FLUENT）. Consequently, it has been shown that the results obtained from the two dimensional approach are consistent with those obtained from the others.展开更多
In order to predict the effects of cavitation on a hydrofoil, the state equations of the cavitation model were combined with a linear viscous turbulent method for mixed fluids in the computational fluid dynamics (CFD)...In order to predict the effects of cavitation on a hydrofoil, the state equations of the cavitation model were combined with a linear viscous turbulent method for mixed fluids in the computational fluid dynamics (CFD) software FLUENT to simulate steady cavitating flow. At a fixed attack angle, pressure distributions and volume fractions of vapor at different cavitation numbers were simulated, and the results on foil sections agreed well with experimental data. In addition, at the various cavitation numbers, the vapor fractions at different attack angles were also predicted. The vapor region moved towards the front of the airfoil and the length of the cavity grew with increased attack angle. The results show that this method of applying FLUENT to simulate cavitation is reliable.展开更多
This paper deals with time dependent performance characteristics of cavitating hydrofoils, the flow around which has been simulated using pressure-based finite volume method. A bubble dynamics cavitation model was use...This paper deals with time dependent performance characteristics of cavitating hydrofoils, the flow around which has been simulated using pressure-based finite volume method. A bubble dynamics cavitation model was used to investigate the unsteady behavior of cavitating flow and describe the generation and evaporation of vapor phase. For choosing the turbulence model and mesh size a non cavitating study was conducted. Three turbulence models such as Spalart-Allmaras, Shear Stress Turbulence （SST） κ-ω model, Re-Normalization Group （RNG） κ-ε model with enhanced wall treatment are used to capture the turbulent boundary layer along the hydrofoil surface. The cavitating study presents an unsteady behavior of the partial cavity attached to the foil at different time steps for σ = 0.8 and σ = 0.4. Moreover, this study is focused on cavitation inception, the shape and general behavior of sheet cavitation, lift and drag forces for different cavitation numbers.展开更多
文摘This paper deals with two new species of the genus Dactylogyrus from marine fishes of Gobiidae. A new subjective synonym that is also a new record in China is concerned.1. Dactylogyrus qinzhouensis sp.nov. (Fig.1, a-b)Type-host: Glossogobius giuri Site: gills Type-locality and date: Qinzhou, Guangxi; May 7,1995 Type-specimens: Holotype no.GXqz1995050701; paratypes no.GXqz1995050702-3 About ten species of Dactylogyrus have been reported from fishes of Bobiidae in the world. This new species is similar to Dactylogyrus soni Gussev, 1995 (gobii Tripathi, renamed) which has the same species of host , but differs from the latter in the shape and size of hamuli, connective bar and copulatory organ. This species has a shorter hamuli (0.050-0.065 mm) and a longer point (0.020-0.022 mm), while the known species with a longer hamuli (0.095-0.102 mm) and a short point. The two laterals of the connective bar of this species are warped and with undulated wave, and the laterals of the connective bar of the known species become thickened and wide. The copulatory organ of the new species has a coiled tube of length 0.115-0.134 mm , the supporting apparatus which has a curve at the end is divided into two lobes at the base, while the length of copulatory tube of the old species is only 0.030 mm, and the supporting apparatus of the known species is also different. So, we regard this species as a new species in science and name it after its locality.2. Dactylogyrus microgobius sp.nov. (Fig. 2,a-b)Type-host: Microgobius gulosus, Microgobius sp.Site: gills Type-locality and date: Qisha, Guangxi; Sep.5,1995 Type-specimens: Holotype no.GXqsha1995090501; paratypes no.GXqsh1995090502; HNhk1998040301 This species is similar to Dactylogyrus gudaoensis Chen, 1982, but distinguishs from the latter in the shape and dimensions of hamuli, connective bar and copulatory organ. The length of the hamuli of this species is distinct smaller than the latter’s. The connective bar of the known species has two tubercules in the middle, while the bar is short and strong without tubercule in this species. The copulatory tube is nearly "S" shaped and the supporting apparatus "Y" shaped in known species and both the copulatory tube and the supporting apparatus are curved as "C" and with a deep fovea near the terminal in this speices. Therefore we regard this species as new and name it after its host. 3. Dactylogyrus bialatus Wu, Wang&Jiang, 1988 has been reported which has the characteristic of being well developed inner root, embryonic type hooklets, being two small knob-like projections in the middle of the connective bar ,and being a slight curved copulatory tube and divided, hook-shaped distal ends of the supporting apparatus etc.. All these important features along with the dimensions of this species (table 1) are nearly the same as that of Pseudodactylogyrus haze Ogawa, 1984. According to the 1961 ICZN, we think that Dactylogyrus bialatus is a subjective synonym of Pseudodactylogyrus haze Ogawa, 1984. Pseudodactylogyrus haze ( syn. D. bialatus) is first recorded in China and Synechogobius ommaturus is a new host of this species.
基金Supported by the Yildiz Technical University Scientific Research Projects Coordination Department.Project Number:2012-10-01 KAP 02
文摘In the present study, a new approach is applied to the cavity prediction for two-dimensional （2D） hydrofoils by the potential based boundary element method （BEM）. The boundary element method is treated with the source and doublet distributions on the panel surface and cavity surface by usethe of the Dirichlet type boundary conditions. An iterative solution approach is used to determine the cavity shape on partially cavitating hydrofoils. In the case of a specified cavitation number and cavity length, the iterative solution method proceeds by addition or subtraction of a displacement thickness on the cavity surface of the hydrofoil. The appropriate cavity shape is obtained by the dynamic boundary condition of the cavity surface and the kinematic boundary condition of the whole foil surface including the cavity. For a given cavitation number the cavity length of the 2D hydrofoil is determined according to the minimum error criterion among different cavity lengths, which satisfies the dynamic boundary condition on the cavity surface. The NACA 16006, NACA 16012 and NACA 16015 hydrofoil sections are investigated for two angles of attack. The results are compared with other potential based boundary element codes, the PCPAN and a commercial CFD code （FLUENT）. Consequently, it has been shown that the results obtained from the two dimensional approach are consistent with those obtained from the others.
文摘In order to predict the effects of cavitation on a hydrofoil, the state equations of the cavitation model were combined with a linear viscous turbulent method for mixed fluids in the computational fluid dynamics (CFD) software FLUENT to simulate steady cavitating flow. At a fixed attack angle, pressure distributions and volume fractions of vapor at different cavitation numbers were simulated, and the results on foil sections agreed well with experimental data. In addition, at the various cavitation numbers, the vapor fractions at different attack angles were also predicted. The vapor region moved towards the front of the airfoil and the length of the cavity grew with increased attack angle. The results show that this method of applying FLUENT to simulate cavitation is reliable.
文摘This paper deals with time dependent performance characteristics of cavitating hydrofoils, the flow around which has been simulated using pressure-based finite volume method. A bubble dynamics cavitation model was used to investigate the unsteady behavior of cavitating flow and describe the generation and evaporation of vapor phase. For choosing the turbulence model and mesh size a non cavitating study was conducted. Three turbulence models such as Spalart-Allmaras, Shear Stress Turbulence （SST） κ-ω model, Re-Normalization Group （RNG） κ-ε model with enhanced wall treatment are used to capture the turbulent boundary layer along the hydrofoil surface. The cavitating study presents an unsteady behavior of the partial cavity attached to the foil at different time steps for σ = 0.8 and σ = 0.4. Moreover, this study is focused on cavitation inception, the shape and general behavior of sheet cavitation, lift and drag forces for different cavitation numbers.
