Hello folks,(adsbygoogle = window.adsbygoogle || []).push({});

I am having difficulty comprehending some material in my fluid dynamics course. This is not a homework question, just something missing in my understanding.

When proving the "Pressure Field Equation," (something I am not yet able to do) there is a series of steps my instructor took.

[itex]P=P_1+\Delta{P}[/itex]

[itex]P=P_1+\Delta{y}\frac{dp}{dy}[/itex]

Which somehow, magically, leads to...

[itex]F_y = (P+\frac{\partial{p}}{\partial{y}}\frac{\delta{y}}{2})*\delta{x}\delta{z}[/itex]

So my question is this.

[itex]\frac{dp}{dy}[/itex] is simply the change of P wrt y

[itex]\frac{\partial{p}}{\partial{y}}[/itex] is the change of p wrt y in a particular direction, or part of the gradiant.

But what in the sam is [itex]\frac{\delta{y}}{2}[/itex]?

Why the delta?

Any help would be appreciated.

Thanks,

Mac

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# Pressure Field Equation / Differentials

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