- #1
fog37
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Hello Everyone,
Bernoulli's equations expresses the conservation of mechanical energy for a particular fluid parcel moving inside a time-independent flow. The parcel is restricted to move and remain along a particular streamlines. The sum of the trinomial is equal to a constant on every different streamline but the various constants are different. In the case of a flying airfoil (wing), we assume that these constants are all the same for the incoming flow and for the curved flow that passes around the wing. Why? What allows us to apply this assumption and considered all the constants equal to each other?
When explaining how a wing flies, both Newton's 3rd law (action reaction) and Bernoulli's principle are applicable and correct but Bernoulli can only be applied outside of the boundary layer where the fluid is considered perfectly inviscid, correct? Newton's law gives a conceptual explanation (air is deflected downward providing a reaction upward force and and backward direction force (drag). Nonetheless, Bernoulli's equation still provides the correct pressure distribution to get the correct lift. Is it because the boundary layer is so thin that we can ignore its presence and therefore apply Bernoulli's equation to obtain the correct pressure distribution around the wing?
Thanks,
Fog37
Bernoulli's equations expresses the conservation of mechanical energy for a particular fluid parcel moving inside a time-independent flow. The parcel is restricted to move and remain along a particular streamlines. The sum of the trinomial is equal to a constant on every different streamline but the various constants are different. In the case of a flying airfoil (wing), we assume that these constants are all the same for the incoming flow and for the curved flow that passes around the wing. Why? What allows us to apply this assumption and considered all the constants equal to each other?
When explaining how a wing flies, both Newton's 3rd law (action reaction) and Bernoulli's principle are applicable and correct but Bernoulli can only be applied outside of the boundary layer where the fluid is considered perfectly inviscid, correct? Newton's law gives a conceptual explanation (air is deflected downward providing a reaction upward force and and backward direction force (drag). Nonetheless, Bernoulli's equation still provides the correct pressure distribution to get the correct lift. Is it because the boundary layer is so thin that we can ignore its presence and therefore apply Bernoulli's equation to obtain the correct pressure distribution around the wing?
Thanks,
Fog37