The reason is, of course, the lower pressure generated by the object moving through the air
How on earth do you think this object generated the lower pressure?
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The reason is, of course, the lower pressure generated by the object moving through the air
That's the most ironic sentence of the day!mcdenife wrote:That makes not sense.
Joking aside, I'd be interested in some references that show it as "completely wrong."mcdenife wrote:In the context of a wing, it is completely wrong to suggest the faster airflow over the top is a side effect of the pressure difference when the main function and design of said wing is precisely to generate that pressure difference to provide lift.
The object moved from one place to another. That left a void where it used to be. Air rushed to fill that void, causing an acceleration of the air. Which was there first? The void that made the pressure difference, which led to the air accelerating or the air accelerating that caused the pressure difference that filled the void?mcdenife wrote:The lower pressure didnt just generate itself. You said it yourself more or lessThe reason is, of course, the lower pressure generated by the object moving through the air
How on earth do you think this object generated the lower pressure?
Oh so you agree that accelerating the air does cause a pressure difference? Tell me this, if you place this same object in a wind tunnel so that it is stationary and pass a stream of air over it, do you think we will still see this pressure difference. By your argument, it shouldnt generate lift since it has not moved so no void to fill where it 'did not' used to be, right?mcdenife wrote:The object moved from one place to another. That left a void where it used to be. Air rushed to fill that void, causing an acceleration of the air. Which was there first? The void that made the pressure difference, which led to the air accelerating or the air accelerating that caused the pressure difference that filled the void?
Air moving over an object is the EXACT same as an object moving through the air.mcdenife wrote:Oh so you agree that accelerating the air does cause a pressure difference? Tell me this, if you place this same object in a wind tunnel so that it is stationary and pass a stream of air over it, do you think we will still see this pressure difference. By your argument, it shouldnt generate lift since it has not moved so no void to fill where it 'did not' used to be, right?mcdenife wrote:The object moved from one place to another. That left a void where it used to be. Air rushed to fill that void, causing an acceleration of the air. Which was there first? The void that made the pressure difference, which led to the air accelerating or the air accelerating that caused the pressure difference that filled the void?
Regarding reference I can refer you to any number of text books/test material etc but you can simply google. My reference are my aeronautics background.
yes that is correct but that question was meant as a counter to this:Air moving over an object is the EXACT same as an object moving through the air.
well I have a masters from cranfield and have worked with cfd (and FE) designing turbine blades (from both mechanical and thermodymics perspectives). I don't claim to be an expert but I do know its fundamentally incorrect to suggest that faster air flow is side a effect of a pressure differential in an airplane wing and not the cause pressure differential. If that were the case then why the floody bell is the wing profiled as it is?The object moved from one place to another. That left a void where it used to be. Air rushed to fill that void, causing an acceleration of the air. Which was there first? The void that made the pressure difference, which led to the air accelerating or the air accelerating that caused the pressure difference that filled the void?
No, he was being ironic, because the second option is obviously wrong.mcdenife wrote:Oh so you agree that accelerating the air does cause a pressure difference?mcdenife wrote:The object moved from one place to another. That left a void where it used to be. Air rushed to fill that void, causing an acceleration of the air. Which was there first? The void that made the pressure difference, which led to the air accelerating or the air accelerating that caused the pressure difference that filled the void?
Pressure differences don't fill voids, objects do (in this case, said "objects" are molecules in the fluid that rush there because the pressure difference forces them to).And there I was thinking we were debating your suggestion that the "faster airflow is a side effect of the pressure difference rather than a cause.I mean no disrespect but I really cannot understand how you can have a masters degree in engineering when you even fail to recognize that to accelerate an object (such as a bit of air) requires an external force (i.e. a pressure differential in case of a fluid). This is not even engineering, this is high school physics.
Talking of contradictions who was it who implied that the faster air speed over the top of the wing creates the lower pressure of pressure differential is bogus. My premise is and has always been; if this is the case how exactly do you think the wing profile creates this differential?The wing is profiled to create that pressure differential. Hollus gave a pretty good explanation on page 2 of this topic, and anydlaurence did the same a few posts ago. As you said yourself: "the main function and design of said wing is precisely to generate that pressure difference to provide lift". I couldn't have said it better, I just don't understand why insist to contradict yourself.
As explained at least 4 times in this topic, the pressure differential is generated because an object is moving through a fluid, leaving a 'void' behind it containing less molecules per volume than the ambient condition (which, for constant density and temperature, is basically the definition of "lower pressure"). And no, whether you are flying through the air or standing still in a wind tunnel makes no difference.mcdenife wrote:Talking of contradictions who was it who implied that the faster air speed over the top of the wing creates the lower pressure of pressure differential is bogus. My was premise is and has always been; if this is the case how exactly do you think the wing profile creates this differential?The wing is profiled to create that pressure differential. Hollus gave a pretty good explanation on page 2 of this topic, and anydlaurence did the same a few posts ago. As you said yourself: "the main function and design of said wing is precisely to generate that pressure difference to provide lift". I couldn't have said it better, I just don't understand why insist to contradict yourself.
Not speed but velocity but I do think that perhaps its time you do stop.So once again I ask you, what is your physically and scientifically sound explanation why higher speed results in lower pressure (and why a wing profile accelerates air)? If you fail again to answer this, I will stop trying to convince you, because then there is no point in having this discussion.
If you observe a change of a in x whenever y does b, it doesnt take a genius to conclude a relationship exists between the 2 and work out that relationship. whats going on at a molecular, atomic, and quantum level or why the sky is blue is splitting hairsmy point is just that it is fundamentally wrong to think that different velocity is the cause and different pressure the effect - it takes only basic knowledge of science to know that it can only be the other way around. To deny this is to deny Newton's laws.