A study of station keeping objects in water using comsol multiphysics

• Main Author: Tan, Simon Wei Hao
• Other Authors: Ho Shen Yong
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Science
• Online Access: http://hdl.handle.net/10356/70577
• Institution: Nanyang Technological University

The aim of this paper is to study how objects remain stationary in moving waters using the software COMSOL Multiphysics. In particular, we study existing examples in nature – fishes. As it is computationally more challenging to model the correct initial conditions for fishes to swim in the right way to stay stationary against oncoming water, we study instead fish swimming in stationary water and use the results in reverse to form conclusions. The first COMSOL application used is to confirm that fishes undulating a backwards travelling wave is more efficient than flapping (pure oscillation). In addition, we also confirmed the empirical equation that relates the undulating frequency to fish velocity for two-dimensional models. The second COMSOL application focuses on achieving the main aim of keeping fishes stationary in moving waters. The relationship between the changeable parameters, frequency and amplitude of the backwards travelling wave, and the drag force was determined. Also, the general shape and size of the structure was determined to be a major factor in reducing the drag force instead of the frequency and amplitude of undulation. Future works will focus more on the details of shape.