Velocity & Trumpet stack design?

[TigWelder]

I've tried creating a velocity stack that slightly protrudes outwards and above the surface with Fillet and Extrude options, but have not been able to figure it out . It must be something simple I'm missing, does anyone know hot make this "trumpet" shape like in these pictures?:

 

[shift1313]

You will want to use a revolve for that feature. Simply draw the 2d cross section(or half of the cross section as it were), then revolve that around an axis.

[bhamze]

I agree with Matt. I tried several different modeling methods and the revolve feature was the easiest by far. Here are some shots.

[shift1313]

since bill mentioned other methods I thought I would show you another way thats pretty easy. The control over the actual shape is far less than that of a revolve but it can be made with two circles and controlling the start/end constraints with directions and angles.

[bhamze]

since bill mentioned other methods I thought I would show you another way thats pretty easy. The control over the actual shape is far less than that of a revolve but it can be made with two circles and controlling the start/end constraints with directions and angles.

 

You learn something everyday. This was pretty cool, thanks Matt.

[shift1313]

No problemo. It works the same with solid lofts, just have to make sure your direction and angle on the constraints are the correct direction. You could also do this in sheet metal and create a die to form the velocity stack but that gets a good bit more involved:)

[TigWelder]

Thank you, you guys are awesome! I will spend several hours trying different shapes and seeing the flow test effects haha...this is addictive .

[shift1313]

I will tell you this. The biggest benefit is going to come by sticking the stack up into the plenum, rather than on the surface of it. The first screen shot will flow a lot better than the second/third. This is because of the friction between the outer layer of air and the surface of the plenum. If the stack isnt against the wall it wont have these eddies which will actually reduce the effective cross sectional area by up to 10%!