Calculating With the Theoretical Approach of The Settling Velocity of Fish Feed Pellets

Abstract

This study, settling velocity of fish feed pellets was investigated using the formula given by Isaacs and Thodos [1]. This formula is accurate for large pellets (larger the 3.5-4 mm diameter). The settling velocity data in the literature was compared to the predictions of this formula and good agreement was found. The formula also has implications on how settling velocity depends on various parameters such as water temperature, salinity, pellet diameter, length, density of pellet etc. Settling velocity was found to be extremely sensitive to errors in density measurements of pellets according to the Isaacs and Thodos [1] formula. A few percent errors in particle density found to cause large deviations in settling velocity. Settling velocity is independent of viscosity according to Isaacs and Thodos formula. The settling velocity was also found to be largely independent of temperature for large pellets. The settling velocity is proportional to square root of diameter according to Isaacs and Thodos formula. This dependence on square root of diameter was demonstrated using the data from Sutherland et al. [2] paper. Salinity was also found to be important parameter. Salinity affects settling velocity by increasing density of water and tends to decrease settling velocity.