Final answer:
Forward and backward surge is high in tanks without baffles due to turbulent wake, which impedes the accuracy of predictions based on the Bernoulli principle. Ballast tanks use flow-through to stabilize despite turbulence.
Step-by-step explanation:
Forward and backward surge is especially high in tanks that are not baffled because such tanks lack the internal structures to dampen the movement of the fluid. Tanks without baffles experience a greater degree of turbulent wake, similar to the disturbance created by large moving objects like airplanes and sailboats. According to the Bernoulli principle, turbulence makes it difficult to achieve quantitatively accurate predictions of fluid behavior, since the principle is only qualitatively correct under turbulent conditions. When considering a ballast tank, which is designed to stabilize a vessel by holding water, ensuring that it undergoes sufficient flow-through—as much as 300% of the tank's capacity—helps to maintain operational stability, even amidst high turbulence.
Forward surge is the movement of water towards the front of the tank, while backward surge is the movement of water towards the back of the tank.
When a tank is not baffled, meaning it does not have compartments or barriers inside, the surges can be particularly high. This is because there are no obstacles to slow down or dampen the movement of water, resulting in a turbulent flow.
For example, imagine shaking a bottle of water with no cap. The water will slosh back and forth, creating surges. Similar to this, the absence of baffles in a tank allows the water to move freely and generate high surges.