Discuss the shape of ship, submarine, fish and birds to effectively explain the impact of Fluid friction on their movement.
Answers
Answer:
The best swimmers have a streamlined shape that ensures an attached flow pattern and a laminar boundary layer at rather large values of the Reynolds number. Simple expressions may be obtained for the volumetric drag coefficient of an ideal body of revolution under laminar unseparated flow conditions together with estimations of a critical value of the Reynolds number. A measure, the capacity-efficiency factor, calculated for different organisms and underwater vehicles, shows that information about animal shapes and locomotion is of utmost biological interest and could be useful to improve robot fish and underwater vehicles as well.
1. Introduction
From the hydromechanical point of view fish swimming is a very complicated unsteady phenomenon. A description of the diversity of fish locomotion and a classification of swimming modes, categories, and styles can be found in Blake [1]. Moreover, recent interest in robot fish requires answering questions about optimal shape and the power necessary for fish locomotion. This study focuses on the most simple estimations of fish drag and power requirements during quasisteady motion when changes in body shape can be neglected. This approach would not be very reliable in the case of anguilliform propulsion, but it is acceptable for the carangi- and thunniforms of the best swimmers