Change notation for mass flow rate from \dot{m} to \tilde{m}. #2645
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The reason is that it's the sum of mass flow rates that give \dot{m}
and the terms are not mass-derivatives.
Closes modelica#2644
chapters/derivationofstream.tex
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| @@ -5,21 +5,22 @@ \chapter{Derivation of Stream Equations}\label{derivation-of-stream-equations} | |||
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| \section{Reasons for avoiding the actual mixing enthalpy in connector definitions}\label{reasons-for-avoiding-the-actual-mixing-enthalpy-in-connector-definitions} | |||
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| Consider a connection set with \emph{n} connectors. The mixing enthalpy | |||
| is defined by the mass balance | |||
| Consider a connection set with \emph{n} connectors, and for the mass flow rates use $\tilde{m}=\text{m\_flow}$. | |||
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Isn't the number of connectors typically denoted $N$ (upper case) in this chapter? (Just wondering; I can see that it is outside the scope of the present fix.)
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It's unfortunately messier. The formulas use
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The upper case symbols aren't only in headings: I think it starts here, followed by lots of other places in stream.tex:
For the following definition it is assumed that
$N$ inside connectors \lstinline!$m_{j}$.c! ($j = 1, 2, \ldots, N$ ) and$M$ outside connectors \lstinline!$c_{k}$! ($k = 1, 2, \ldots, M$ ) belonging to the same connection set
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On the other hand, it is ugly to use uppercase $N$ and $M$, so I'd be strongly in favor of going in the direction of $n$ and $m$, but don't know what conflicts that would cause.
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Ah, I see in the stream-chapter N and M are used in the Modelica code, but in this appendix that is mostly math
I agree that n and m would be more common, but will place that in another PR (it's primarily for the stream-chapter).
Co-authored-by: Henrik Tidefelt <henrikt@wolfram.com>
I agree that would be ideal. |
Friendly reminder: @hubertus65 @casella (if there are additional fluid-experts, please be vocal) do you agree with this PR using |
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We would still appreciate input from a fluid-expert, but we cannot wait too long for that - so if we don't hear anything from fluid-experts by next week I think we will have to manage without. |
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Adding approval, just so that @HansOlsson can proceed with this in case there is still no feedback from fluid experts in a week from now.
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Sorry for the delay, thermal engineers often use \dot{m} for mass flow rate. As a control engineer, I really hate that, because in the context of dynamical systems it seems that m is a state, never mind writing dynamic equations with inertial effects, which would become m with two dots.... I myself use w for the mass flow rate. I guess \tilde{m} would also be fine, in any case I don't think this is a big deal. |
The reason is that it's the sum of mass flow rates that give \dot{m}
and the terms are not mass-derivatives.
Closes #2644