which of the black triangles has less drag?

>>8309051
depends on the material, but presumably the upper one

>>8309051
The right one, because the air blowing past it pushes down on the top and bottom, thus producing forward lift.

>>8309051
unless the dimensions are incredibly small, the top one has far less drag

>blue arrows represent air moving from left to right

>arrows are pointed to to left

This is stupid

Isn't drag only depended on cross section? There may be other forces but drag should be the same.

>>8309997
Not *your* left and right, silly. It's from the point of view of the wind.

quite good

>>8309051
If these were cars on a highway, I'd rather drive behind the top one.

>>8309051
Considering the air is a newtonian fluid, the top one suffers more drag. Because it has more surface in contact with the particles pushing the object.
The difference between the two wouldn't be noticeable still, unless those are 10 meters long or so.

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>>8309663
>The right one

>>8310862
lel no
Form drag is much more significant than skin drag

>>8310866
Source?

>>8309051
Probably the top one.

The drag equation is [math] D = \frac{1}{2} \rho v^2 S C_D [\math]

Since [math] \rho,v^2 [\math] are constant we have to consider only the surface area and the drag coefficient.

In the bottom one, the main cause of drag is skin friction. This is relatively more benign.

In the top one, after all the skin drag leading up to the abrupt termination of the shape, the wedge will experience boundary layer separation which results in vortex shedding, greatly lowered pressure downstream and the resulting very high pressure drag in addition to pressure drag.

This is my initial instict however. In many cases like this, you have to do CFD or an actual physical test to be sure.

Also this assumes that the two wedges are sufficiently far apart to ignore blockage etc.

>>8310869
The two courses I took on fluids and the associated lab.
The fluid has to completely stop and reroute on the bottom one. You'll have vortex shedding and wakes forming in both cases, but only the bottom one requires a full stop and reroute of the fluid
think of it this way, if you poured water over both of the standing upright in the sink, which one would feel heavier after you start pouring water over it?

>>8310880
this is of course assuming the fluid flow is going in the direction of the arrows, and not "from left to right" as stated in the problem, opposite the direction of the arrows

>>8309051
build some light weight models with the center of mass exactly half way the overall length. throw them in different alignments.

the result may surprise you.

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>>8310882
aaand here it is.
drag coef. larger for bottom than top, assuming equal dimensions

>>8309051
is the mass equally distributed?

>>8310908
makes no difference on the drag, senpai

>>8310915
but on the aerodynamic stability.

>>8310917
>which of the black triangles has less drag?

Clearly the top triangle has the most aesthetically appeasing direction. I think all triangles should point to the right. And this concludes my report on which direction should a triangle point.

>>8309051
first one will produce more turbulence

>>8310935
>I think all triangles should point to the right.
>>>/pol/