![]() A spinning ball doesn't cause the reduction. The ball spins because with more air over the top, the viscosity in the boundary layer has more drag than on the bottom. More air accelerated around the upper part causes a lower pressure. I don't know if any perfume atomizers use jet ejectors (also educator)ġ0:37 - The centering of the ball is also Coanda. You can make an atomizer with a jet pump, or a curved two-pipe flow. The viscosity caused entrainment draws fluid along which causes the lower pressure to draw more into the entrainment region. Not too clear, but uses the word entrain. ![]() I've done it.ħ:18 - The "tube quite like that one residing in the atomizer" appears to be a jet pump. A 'Tee' will only blow bubbles in the reservoir. the flow hits the draw tube and curves over it.Ħ:34 - The way he draws it will not work because there is no curved flow. I haven't worked out the physics on this yet, but the funnel version can be Coanda, but the flat plate is more complex.Ħ:30 - A real atomizer has two tubes, not a "Tee". This is the atomizer.ĥ:47 - This is paired with what is called Bernoulli Levitation. Wind over the top can cause lowered pressure, but is due to a curved flow.ĥ:08 - The flow curves around the top of the tube, plus he angles the flow upward which includes some entrainment. Anyone owning one knows you must create a good updraft with a good fire to start it. Note that is is stationary water, but moving ships suggesting the problem.Ĥ:34 - Chimney draft is due to the heat of the fire heating air. This is poorly executed with all that flapping which isn't necessary.ģ:40 - Balls is Coanda, a curved path, not the speed, reduces the pressure.ģ:54 - Ships passing. He makes the all too common mistake of conflating increasing speed (acceleration) with just speed.Ģ:20 - Bernoulli does not explain why a plane flies, Curve ball, chimney draft, bird soaring, boomerang.ģ:00 - Blow over paper is first a curved flow, thus Coanda, then entrainment once the paper goes straight. ![]() Julius Sumner Miller normally quite good, really blows this one. We hire chaps educated in Asia - they are still taught properly. 2000's graduates are useless - they don't even want to think. 1980's graduates weren't quite as good, but they had the basics and could still think. 1970's school graduates were capable and knew their stuff. That's a big part of why we parents have no respect for schools and school teachers these days. Me: "So, according to the kinetic theory, the pressure changes, doesn't it? What sort of change?" Me "Did you get taught the kinetic theory of gasses at your school?" hang on, sorry, I forgot to relate it to absolute zero - er, um, it will go up a little bit."Ģ000's: Me: I have a quantity of gas in a rigid sealed container etc etc Me: What if I start at 25 degrees farenheit and take it to 50 farenhiet? Young job applicant: The pressure will double. "ġ980's: Me: I have a quantity of gas in a rigid sealed container etc etc Young job applicant, without any hesitation: "It will go up about 10% or so. ![]() In the 1970's: Me: "I have a quantity of gas in a rigid sealed container at 1ATM and 25 C. In my career I got to interview young chaps who had applied for technical jobs. This may not apply to you, but it's generally true. Lack of respect for teachers is inevitable today as teachers get fairly low pay. That won't apply to your field, but probably the rot has set it before they come to you. Today, they get taught a lot of disconnected facts and just see it as meaningless work. This tended to lead students to get quite interested, as they believe that more study leads to more understanding about the world. When I was at school, science was taught by first establishing fundamentals, then building on that. That's the wrong approach - it has meant that neither girls nor boys enjoy school. ![]() But those who design school syllabi got concerned that girls didn't, and they dumbed down the syllabi. When I was at school, boys & teenagers actually enjoyed science and manual arts subjects. As I said in an earlier post, my cousin who was a teacher retired early even though she had a passion for teaching, because she was getting more an overloaded with paperwork and having to make detailed teaching plans for each individual student in ever-increasing class sizes. Your experience is similar to what I've heard from other teachers, though student disinterest quite as bad as you describe in a trade school environment is I think unusual. Keit Hammleter Vercammen : To a significant degree I sympathise with you. ![]()
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