What type of flow do non-positive displacement pumps typically handle?

Non-positive displacement pumps are designed to handle variable non-viscous flow. These pumps operate by using rotational energy to move fluid, which allows them to adapt to changes in flow demand and handle a wider range of flow rates. This characteristic is particularly useful in applications where the fluid properties can change, as these pumps can handle fluctuations without being affected by pressure changes in the system.

The ability of non-positive displacement pumps to manage variable flow is due to the way they draw in and expel fluid. Unlike positive displacement pumps, which pump a fixed amount of fluid with each cycle, non-positive displacement pumps can adjust their output based on the resistance and requirements of the system, resulting in the capability to accommodate varying flow conditions. This makes them ideal for applications where the viscosity of the fluid is low and where changes in flow rate are frequent.

In contrast, the other options describe more specific conditions or limitations that do not align with the operational characteristics of non-positive displacement pumps. This is why 'variable non-viscous flow' is the accurate choice, emphasizing the pump's capability to handle various flow rates without being restricted to a specific fluid type or viscosity.