Please someone help me. There is an example from TBR Physics Part II that is tripping me up: 7.6b.
In calibrating a flow meter, an engineer measures the total pressure drop across a pipe as a function of the gas flow velocity. Which of the following plots BEST details his results?
The answer is B, and I attached a drawing.
In the explanation they say fluids flow from regions of higher pressure to regions of lower pressure in order to get a fluid (such as a gas to flow).
My question is: to obtain a ΔP such as +5 Pa as shown on the graph it would require a positive P2 (say 10) minus a smaller positive P1 (say 5). I would think that if ΔP is positive, and thus it is going from a region of low pressure (P1) to high pressure (P2), that this would lead to flow in the reverse direction (i.e. negative velocity), but as you can see on the chart, a positive ΔP of 5 Pa corresponds to a positive velocity of about 5 m/s.
This doesn't really make sense to me, so could someone please help clarify? Thanks so much!
Ryan
In calibrating a flow meter, an engineer measures the total pressure drop across a pipe as a function of the gas flow velocity. Which of the following plots BEST details his results?
The answer is B, and I attached a drawing.
In the explanation they say fluids flow from regions of higher pressure to regions of lower pressure in order to get a fluid (such as a gas to flow).
My question is: to obtain a ΔP such as +5 Pa as shown on the graph it would require a positive P2 (say 10) minus a smaller positive P1 (say 5). I would think that if ΔP is positive, and thus it is going from a region of low pressure (P1) to high pressure (P2), that this would lead to flow in the reverse direction (i.e. negative velocity), but as you can see on the chart, a positive ΔP of 5 Pa corresponds to a positive velocity of about 5 m/s.
This doesn't really make sense to me, so could someone please help clarify? Thanks so much!
Ryan
