Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
EXPERIMENTAL DETERMINATION OF ADDED MASSES FOR AN OPEN FRAME ROV THROUGH DAMPED FREE OSCILLATIONS
Submission Author:
Paola Fonseca , SP , Brazil
Co-Authors:
Paola Fonseca, Juan Pablo Julca Avila
Presenter: Paola Fonseca
doi://10.26678/ABCM.COBEM2023.COB2023-2422
Abstract
The main objective of this work is to determine the added masses in surge, sway, and heave directions of an open-frame ROV used for the stock assessment of scallops on the Peruvian coast. The method consisted of supporting a 1:3 scale model of the prototype through springs and making it oscillate freely in still water with different amplitudes and frequencies. The Reynolds Number (Re) of the tests were in a range of 0.14×10−5≤ Re ≤0.67×10−5. The acceleration of the model vibrating freely and damply in water was measured experimentally. The added mass in one motion direction was determined using the damped natural frequency equation for a system mass-spring-damper of 1-DOF. The results demonstrated that for Keulegan–Carpenter numbers (KC) in the range of 1.52≤ KC ≤ 3.43, the added mass values were similars between them for the heave direction, there was no significant variation of the added masses within the frequencies, and amplitudes imposed in the tests. In naval and oceanic engineering, the added mass of a body moving in water is usually determined using the simplified form of the damped natural frequency equation, where the damping effects are not considered. However, this work suggests that the simplified form can be used with good accuracy for K C ≤ 0.46, but for KC ≥ 1.52 must be used the exact form of the equation because the damping effects influence more and more by increasing KC.
Keywords
added mass, underwater vehicle, free vibration test, damping effects
