The undulatory dorsal/median fin propulsion modes as represented by amiiform and balistiform fish are of great significance for bionic propulsion research, particularly for the design and control of underwater vehicles, which are generally employed at slow speeds, offering greater maneuverability and better propulsive efficiency.

Visualization and measurement study of vortex flow over delta wing with dorsal fins

5° sweep angle and combination of the identical delta wing with low dorsal fins.

The purpose of the present paper is to investigate the characteristic feature of the aerodynamics of a nose cone at a high angle of attack and study the vortex stability problem for the flow over a flat-plate delta wing with the dorsal fin.

Our interest was aroused by Cai′s theoretical conclusion concerning the effect of dorsal fin height on symmetry and asymmetry of vortex(separation vortex) pairs over slender conical wings and bodies~([3]).

This paper deals with the numerical solution of the Euler equation for airfoils using approximate boundary conditions and the effects dorsal fin on vortex over delta wing at high angles of attack.

The fish is propelled by undulations of a long-based dorsal fin while the body axis is in many cases held straight in swimming.

The annuli on scale,opercular,dorsal fin spine,vertebra and cleithrum of Tor(Folifer) Brevifilis Brevifilis Peter were observed carefully and also the age of the species was diagnosed on the basis of 316 specimens collected respectively from the Qingshui River and the Duliu River in Guizhou,China.