hydrostatics
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Ask if there is a problem with the formula related to atmospheric pressure; PBgR seems to have an issue
If everyone thinks it’s correct and you have doubts, please share your thoughts so that others can analyze them and help correct them for you
Pa=Pa’; Pa is the pressure at point P+a relative to the connection port of the horizontal pipe, while Pa’=P_atmosphere+pAgR. This is the equation for the pressure at point a, but without knowing the height from point a to the connection port, it is not possible to determine the pressure at that point. The formula in the diagram seems to be simply pBgR, right? I am ignorant; I hope everyone can point out my mistakes.
Pa=Pa’; Pa is the pressure at point P+a relative to the connection port of the horizontal pipe, while Pa’=P_atmosphere+pAgR. This is the equation for the pressure at point a, but without knowing the height from point a to the connection port, it is not possible to determine the pressure at that point. The formula in the diagram seems to be simply pBgR, right? I am ignorant; I hope everyone can point out my mistakes.
R is observable; this form of pressure measurement is intended to represent R
The purpose of a differential manometer is to use the liquid level difference R to represent the pressure difference. What I mean is that I have some questions regarding the formulas in the diagram that are related to the atmosphere; those questions are also mentioned in the reply, and I hope for an answer.
This is a special case: gas flows within the pipe, and its density is similar to that of air; therefore, the static pressure at point a relative to the connection point of the pipe is ignored； Or, based on the transmissibility of pressure, the points at a distance R from point a have the same pressure as inside the pipe, which is p
According to this, the formula in the diagram has constraints: the fluid in the pipeline is a gas, and its density is approximately equal to that of air. If the fluid is a liquid or its density is not approximately equal to that of air, then the pressure from point a to the connection port cannot be ignored. If the height from point a to the connection port is h, then Pa = P + pBgh. Pa’ = P_atmosphere + pAgR. Rearranging gives P – P_atmosphere = pAgR – pBgh. So, it’s necessary to know the height h as well, right?