So, these vibrations can lead to harmful effects on the ship, causing vibration in the accommodation or even causing vibrations inside engine room or in particular locations depending on what type of ship, what type of flow disturbance you have. So, it is many times required to visualize the flow through a model experiment, now, how do you visualize the flow? We have seen that flow can be, we can understand something about the flow by means of a paint flow test- I have mentioned this before- and sometimes we use wool tufts, small woolen threads attached by means of pins to a model body at various locations, and when the flow past it is seen either through a glass panel mounted on the wall of the towing tank, which generally not the case, or by video recording the flow, the wool tuft positions on the side of the model and we can realize if the flow is stream lined or there is existence of separated flow- in that case, it is possible to modify the model shape and do the test again.
Sometimes we may do the model test for finding