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Search: Posts Made By: HazelNuts39
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Forum: Tech Log
4th Dec 2012, 21:19
Replies: 388
Views: 99,890
Posted By HazelNuts39

Does he need defending? After all, he's not...

Does he need defending? After all, he's not responsible for the misconceptions based on wrong applications of his equation!
Forum: Tech Log
3rd Dec 2012, 17:18
Replies: 388
Views: 99,890
Posted By HazelNuts39

Who is Ms 39? It wasn't me!

Who is Ms 39? It wasn't me!
Forum: Tech Log
3rd Dec 2012, 13:48
Replies: 388
Views: 99,890
Posted By HazelNuts39

Maybe we should consider that the downwash...

Maybe we should consider that the downwash produced by the lifting wing doesn't change in ground proximity, but is reflected by the ground as an upwash. The wing benefits from the upwash in a manner...
Forum: Tech Log
2nd Dec 2012, 22:04
Replies: 388
Views: 99,890
Posted By HazelNuts39

Perhaps the 'effective' aspect ratio is...

Perhaps the 'effective' aspect ratio is increased?

TM1095 compared to Jeff Scott curve:
http://i.imgur.com/HqhRt.gif?1
Forum: Tech Log
1st Dec 2012, 22:13
Replies: 388
Views: 99,890
Posted By HazelNuts39

Lyman, I would rather say that the changes...

Lyman,

I would rather say that the changes in pressure are due to the increase of effective AoA, which in turn is the result of the reduced downwash induced by the vortex system, or rather by the...
Forum: Tech Log
1st Dec 2012, 21:51
Replies: 388
Views: 99,890
Posted By HazelNuts39

IMHO the increase in pressure under the wing is...

IMHO the increase in pressure under the wing is not as great as the decrease in pressure above the wing.
Forum: Tech Log
1st Dec 2012, 21:05
Replies: 388
Views: 99,890
Posted By HazelNuts39

The pressure distribution around the wing is not...

The pressure distribution around the wing is not different from that it has out of ground effect at a somewhat greater angle of attack. IOW, no zones of 'trapped air'.
Forum: Tech Log
1st Dec 2012, 19:49
Replies: 388
Views: 99,890
Posted By HazelNuts39

Only in absolute terms, because the low aspect...

Only in absolute terms, because the low aspect ratio wing has a high induced drag. Percentage wise there is no change with aspect ratio, see graph "Percentage of normal induced drag vs percentage of...
Forum: Tech Log
1st Dec 2012, 16:08
Replies: 388
Views: 99,890
Posted By HazelNuts39

Machinbird, Good article. But why only the...

Machinbird,

Good article. But why only the trailing vortices and not the 'bound' vortex from wing tip to wing tip?

Reminds me of how 'ground effect' is modeled in CFD. Imagine an identical...
Forum: Tech Log
1st Dec 2012, 08:01
Replies: 388
Views: 99,890
Posted By HazelNuts39

The element of 'scale' is represented by the...

The element of 'scale' is represented by the Reynolds number. For some tests it is important, for many it is not. NASA has or had a 'variable density' tunnel that permitted variation of Re...
Forum: Tech Log
19th Nov 2012, 09:30
Replies: 388
Views: 99,890
Posted By HazelNuts39

Google is your friend: The bathtub vortex problem...

Google is your friend: The bathtub vortex problem (http://jpsj.ipap.jp/news/jpsj-nc_109.html)

Another one: Which way? (http://math.ucr.edu/home/baez/physics/General/bathtub.html)
Forum: Tech Log
17th Nov 2012, 15:18
Replies: 388
Views: 99,890
Posted By HazelNuts39

Mr Optimistic, Isn't Coriolis...

Mr Optimistic,



Isn't Coriolis responsible for that? Or is it viscosity?
Forum: Tech Log
15th Nov 2012, 01:01
Replies: 388
Views: 99,890
Posted By HazelNuts39

Physically it doesn't really matter whether you...

Physically it doesn't really matter whether you place yourself in the airplane and describe the airflow moving by, or you place yourself in air at rest and look at the airplane flying past you. If...
Forum: Tech Log
14th Nov 2012, 22:45
Replies: 388
Views: 99,890
Posted By HazelNuts39

I think that picture shows the distribution of...

I think that picture shows the distribution of downwash velocity at some distance behind the wing (10x wingspan), where the trailing vortex sheet has 'rolled up' into two discrete vortices. Would the...
Forum: Tech Log
14th Nov 2012, 16:44
Replies: 388
Views: 99,890
Posted By HazelNuts39

The wind blows from high pressure to low...

The wind blows from high pressure to low pressure. Viewed from the high pressure area, it looks like being pushed outwards. In the center of a hurricane, it looks more like suction. It all depends on...
Forum: Tech Log
27th Oct 2012, 10:31
Replies: 388
Views: 99,890
Posted By HazelNuts39

OG; Yes, if one arbitrarily assumes ... ...

OG;

Yes, if one arbitrarily assumes ...

EDIT::
OTOH, if one equally arbitrarily assumes that the uniform downwash velocity is that predicted by Prandtl for the 'lifting line', the area...
Forum: Tech Log
23rd Oct 2012, 16:16
Replies: 388
Views: 99,890
Posted By HazelNuts39

Well, at subsonic speeds, it is infinite, in all...

Well, at subsonic speeds, it is infinite, in all directions. Any boundary is arbitrary.
Forum: Tech Log
20th Oct 2012, 15:05
Replies: 388
Views: 99,890
Posted By HazelNuts39

Lyman, The entire circle. But of course the...

Lyman,

The entire circle. But of course the downwash velocity is not constant. It reduces with the distance to the wing asymptotically to zero at infinity.
Forum: Tech Log
20th Oct 2012, 12:56
Replies: 388
Views: 99,890
Posted By HazelNuts39

According to A&E, L = mdot*vv. Assuming that all...

According to A&E, L = mdot*vv. Assuming that all the mass captured in the "virtual scoop" uniformly gets a downwash velocity vv, the power required for this is Pi=0.5*mdot*vv^2. Equating this to the...
Showing results 1 to 19 of 19


 
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