When is cavitation most likely to occur in a hydraulic system?

Cavitation occurs when the pressure in a hydraulic system drops below the vapor pressure of the fluid, leading to the formation of vapor bubbles. An abrupt change in pressure can create areas where the pressure is significantly reduced, making it favorable for cavitation to initiate. This situation is particularly likely in scenarios where the fluid experiences rapid changes in velocity or direction, such as in pumps or at bends in piping systems.

When fluid flows too slowly, it typically maintains adequate pressure, reducing the risk of cavitation. Similarly, during rapid fluid temperature changes, although viscosity may be affected, it does not directly lead to cavitation unless the pressure conditions are coincidentally right for vaporization. Lastly, overly viscous fluids tend to flow less easily and maintain higher pressure in a system, further decreasing the likelihood of cavitation. Thus, abrupt pressure changes are the critical factor that makes option B the most suitable answer.