Which fluid condition can lead to inaccurate readings on a pressure gauge?

Pulsation in fluid flow can significantly affect the accuracy of pressure gauge readings. This phenomenon occurs when there are fluctuations in pressure caused by the movement of the fluid, such as in systems where pumps are cycling on and off or where there are rapid changes in velocity. These pressure variations can result in the gauge registering momentary spikes or drops in pressure, giving a false impression of the actual system pressure at any given moment.

Mechanical pressure gauges rely on the steady state of fluid pressure to provide accurate readings. When pulsation is present, it disrupts the equilibrium and can cause the gauge needle to oscillate, making it difficult to ascertain a true static reading. Furthermore, sustained pulsation can potentially lead to wear or damage to the gauge over time, compounding the inaccuracies.

In contrast, high viscosity and low temperature can influence the responsiveness of the fluid but do not typically cause the same degree of fluctuation and erroneous readings that pulsation does. Stagnant fluid conditions, while they could lead to reading inaccuracies in some contexts (such as if a gauge is placed on a stagnant side of a system), primarily don’t present the same acute measurement issues as moving fluid under pulsation. Hence, pulsation is the most direct cause of inaccurate pressure gauge readings