How does thermal expansion affect hydraulic fluids?

Thermal expansion is a fundamental principle in fluid dynamics that directly impacts hydraulic systems. As temperature increases, the kinetic energy of the molecules within hydraulic fluids also increases, leading to a greater volume of fluid—this phenomenon is referred to as thermal expansion. As a result, a rise in temperature will not only increase the fluid volume but may also lead to an increase in pressure within a closed hydraulic system.

In a sealed hydraulic system, this change in volume from thermal expansion can result in increased pressure that may affect system performance, potentially leading to hazards such as overpressure conditions or damage to equipment. It's crucial for system designers to account for temperature variations to prevent issues associated with changes in fluid volume and pressure.

Other options don’t accurately represent the impact of thermal expansion on hydraulic fluids. Since thermal expansion specifically relates to changes in volume and pressure, the answer correctly highlights the critical nature of these changes in hydraulic systems.