- #1
fisher garry
- 63
- 1
Homework Statement
The texts are taken from
http://ingforum.haninge.kth.se/armin/fluid/exer/deriv_navier_stokes.pdf
and
https://simple.wikipedia.org/wiki/Stress_(mechanics)
Homework Equations
The Attempt at a Solution
The formula for stress is ##\sigma=\frac{F}{A}## (I). From the document above it is also seen that
$$T_{x}=(\sigma_{xx},\sigma_{xy},\sigma_{xz})$$[/B]
If one looks at the drawing for $$T_{x}$$ and for simplicity sets $$\sigma_{xy}=0,\sigma_{xz}=0$$ so that $$T_{x}$$ is normal to the zy-plane. Then from
$$F_x=T_{x}n_{1}$$
and (I) one should obtain that
$$F_x=T_{x}n_{1}=\sigma A$$
But I don't get how this is correct. Can someone show a derivation