Tube for thought

[Blue Falcon]

Actually you are more of a passive observer to the technical discussion.

Once I realized there was no actual measureable benefit to a redesign of the horn, it was no longer technical and I sat back with my popcorn and watched...threw a fishing line out...waited for a bite. Said from the beginning... can't see any real benefit....then my sarcasm ensued. Nothing new or fundamentally productive came out of this for guidance to the OP. The wheel was successfully reinvented again. i just saw a bunch of cut and pastes from Wikipedia pages and I'm suspect as to if anyone has any practical application of the formulas, principles and theories. But if your having to prove your point for a 2 inch long air horn that is fine the way it is....then go ahead.

[GregT]

Break it down simpler... suck, bang, blow.... we are just discussing how it sucks.

I don't think you're taking this seriously....and I applaud you for that, LOL

I think Sharpy's had good value for his money starting this one.....

[posplayr]

Once I realized there was no actual measureable benefit to a redesign of the horn, it was no longer technical and I sat back with my popcorn and watched...threw a fishing line out...waited for a bite. Said from the beginning... can't see any real benefit....then my sarcasm ensued. Nothing new or fundamentally productive came out of this for guidance to the OP. The wheel was successfully reinvented again. i just saw a bunch of cut and pastes from Wikipedia pages and I'm suspect as to if anyone has any practical application of the formulas, principles and theories. But if your having to prove your point for a 2 inch long air horn that is fine the way it is....then go ahead.

Funny,I now realize you were the one pointing out to me that I was using "the wrong formula". How would you know?

What you don't understand is I'm not working on a 2" pipe.

What I was doing is providing ample theoretical principle of the venturi/vortex principle to suggest there is clear application, something which you even enumerated early on.

The only thing I can see you are doing now is crowing about is that you don't like science, or engineers.
What is it you don't like, somebody sitting here at their keyboard and pulling back the veil of secrecy on you practical experience?

[Blue Falcon]

Funny,I now realize you were the one pointing out to me that I was using "the wrong formula". How would you know?

What you don't understand is I'm not working on a 2" pipe.

What I was doing is providing ample theoretical principle of the venturi/vortex principle to suggest there is clear application, something which you even enumerated early on.

The only thing I can see you are doing now is crowing about is that you don't like science, or engineers.
What is it you don't like, somebody sitting here at their keyboard and pulling back the veil of secrecy on you practical experience?

If you wanted to talk about anything BUT the horn in the OP example... there is another thread in the forum. This one albeit is for the 2 inch horn, as for the formula.... because ... as in my sig... worked on, around, in, above, below jet engines for 20 years.... I learnt a few tings. I have no need to toot my own horn about when, what, where I have been, worked on and made miracles happen. I dropped the mic and walked away from my career never looking back when I retired. I walked completely away from the gas turbine world, and by gas turbine I also mean ancillaries like power distribution, electronics, micro miniature repair, diesel engines, fuel refinery, IMA (your DoD, you should know this one) boilers, air systems, HVAC and refrigeration... There is not much I didn't do in my career and not many schools they didn't send me too. I walked away so I could take a job I ENJOYED and not one I contractually HAD to do. I was tired of being flown all over to fix things other people with the same training couldn't or wouldn't. If I ever see another Raytheon technician and the words "turn it off for 5 minutes then turn it back on and see if the fault clears" come out of his mouth, I will end him. aka. "Raytheon Reset" What practical experience do I have? I have enough, that's your answer. And why do I break it down so simple? In the end, 95% of it can always be broken down to simplicity of logic, yes or no. Why post a theory that was for fluids when the same rules don't apply to gases due to compressibility.. answer.. who cares in this case.. has no impact on the horn the OP posted.

Science, love science and I am an engineer... I just don't care for long winded will never make an impact on subject of the post stuff. that's all ( yes the science is there, but will have no major impact to redesign the horn to make it the application any more efficient than it already is... reinvent the wheel)

[Blue Falcon]

I don't think you're taking this seriously....and I applaud you for that, LOL

I think Sharpy's had good value for his money starting this one.....

Rule 62 ..... I'm a rockstar at it.... now lets see if anyone gets the irony.

[posplayr]

If you wanted to talk about anything BUT the horn in the OP example... there is another thread in the forum. This one albeit is for the 2 inch horn, as for the formula.... because ... as in my sig... worked on, around, in, above, below jet engines for 20 years.... I learnt a few tings. I have no need to toot my own horn about when, what, where I have been, worked on and made miracles happen. I dropped the mic and walked away from my career never looking back when I retired. I walked completely away from the gas turbine world, and by gas turbine I also mean ancillaries like power distribution, electronics, micro miniature repair, diesel engines, fuel refinery, IMA (your DoD, you should know this one) boilers, air systems, HVAC and refrigeration... There is not much I didn't do in my career and not many schools they didn't send me too. I walked away so I could take a job I ENJOYED and not one I contractually HAD to do. I was tired of being flown all over to fix things other people with the same training couldn't or wouldn't. If I ever see another Raytheon technician and the words "turn it off for 5 minutes then turn it back on and see if the fault clears" come out of his mouth, I will end him. aka. "Raytheon Reset" What practical experience do I have? I have enough, that's your answer. And why do I break it down so simple? In the end, 95% of it can always be broken down to simplicity of logic, yes or no. Why post a theory that was for fluids when the same rules don't apply to gases due to compressibility.. answer.. who cares in this case.. has no impact on the horn the OP posted.

Science, love science and I am an engineer... I just don't care for long winded will never make an impact on subject of the post stuff. that's all ( yes the science is there, but will have no major impact to redesign the horn to make it the application any more efficient than it already is... reinvent the wheel)

No one is asking for a resume, just a productive conversation.

BTW My first job out of college was RTN EW in Santa Barbara (Jan 1980).

[sharpy]

"You do realise that if the coriolis force was to be of any use, you'd have to make them with the twist going one way for the Northern hemisphere - and the opposite way for us down here...."

greg , thats utter crap. LOL Bet you the stacks on left LHS go clockwise and the Stacks on RHS go anticlockwise works heap better, But im thinkn the general consent is they look trick. i hope

[Blue Falcon]

No one is asking for a resume, just a productive conversation.

BTW My first job out of college was RTN EW in Santa Barbara (Jan 1980).

Nuke EM (de-nuked for medical reasons..they don't like seasonal allergies for some reason), then converted GSE ( I was the only 2M tech on ship with a clearance....I've seen a lot.. ) I had enough NEC's for continuation page on my DD-214 lol , then contractor after retirement for a very short time...before I walked away, bureaucracy was never my strong point and I had enough. Swore I would never take another job where I had to dress up or wear a suit. Doing what I love to do now and getting paid to do it now. The ability to not have to think and just do is sooooo satisfying...makes up 70% of my current week and offsets the 30% I actually do have to think.

So you're telling me you are familiar with the "Raytheon Reset"

dang...now I'm super off topic.... well poo

[Blue Falcon]

"You do realise that if the coriolis force was to be of any use, you'd have to make them with the twist going one way for the Northern hemisphere - and the opposite way for us down here...."

greg , thats utter crap. LOL Bet you the stacks on left LHS go clockwise and the Stacks on RHS go anticlockwise works heap better, But im thinkn the general consent is they look trick. i hope

Ok... I'll do a "for reals" post. Raised tubes may whistle, recessed would be cooler. Raised tubes also give a chance for FOD.

[dorkburger]

Break it down simpler... suck, bang, blow.... we are just discussing how it sucks.

You forgot squeeze.....Thats about all I can add. The knowledge and understanding of physics here is far beyond my level......I sometimes wonder why you guys tinker with stone age GS motorcycles.....But im glad you do.

[posplayr]

You forgot squeeze.....Thats about all I can add. The knowledge and understanding of physics here is far beyond my level......I sometimes wonder why you guys tinker with stone age GS motorcycles.....But im glad you do.

The sophisticated simplicity of the mechanical enginnering (engine) design on top of the basic dynamic complexities of how a motorcycle works, but most important is that they are dirt cheap .

[posplayr]

Ok... I'll do a "for reals" post. Raised tubes may whistle, recessed would be cooler. Raised tubes also give a chance for FOD.

Cold formed steel tube with alternating concave, convex (inside/outside) grooves. Would be very cheap. CNC the cold formed tooling like at a muffler shop. Tig welded flanges or aluminum flare for inlet?

What is FOD?

[dorkburger]

I took it as Foreign Object Damage, but as stated earlier, I'm not that smart.....

[Blue Falcon]

I took it as Foreign Object Damage, but as stated earlier, I'm not that smart.....

You Sir are correct.

[Joe Garfield]

Maybe this has all been said - I read about 2 pages. I particularly like this topic so I felt like thinking and writing about it. But reading the last post, I think I came to the same conclusion (a polished surface)....

3D printing has horrible surface finish.

One of my projects at work was designing Venturi hardware for aircraft engine fuel injectors. There was a measured 10% increase in pressure drop of additive manufactured (3d printed) metal parts versus cast parts, and this is after almost 2 decades of process refinement to get a better surface finish. A smooth (polished) surface would be ideal but would be too expensive considering the complexity of the part. I haven't seen ANY plastic 3D printed parts that come anywhere close to the finish on the printed metal, except maybe SLA but I don't think it's as good.

I had a pair of skis in the '90s that had dimples. The idea was that the dimples carried air pockets with the skis, and there should be less friction between the air pockets and free stream air, versus the ski material and free stream air.

Golf ball dimples add turbulence around the ball (I think this has been said already) to help air stay attached to the surface and reduce the size of the high pressure zone behind the ball, creating less drag. The turbulence would actually create more surface drag, but the gain of pressure drag reduction outweighs that penalty. Plus the engineers can alter the trajectory of the flight path based on predictions of ball velocity and rotation rate.

So a dimpled surface would actually create turbulence and slow the air down, rather than speed it up. Turbulence is non-laminar flow, so if particles are travelling in any direction other than into the pipe, there is a loss in flow velocity.

Also, the boundary layer exists 360 degrees around the circumference of the pipe, so tripping or enlarging the boundary layer reduces the effective flow area (less area of unobstructed air flow). I would think you want a small boundary layer to create the largest effective flow area.