This is a two-dimensional wind tunnel with a test section that is 48 inches high, 36 inches long, and 2.5 inches deep. The sides of the wind tunnel are made of glass. Air is pulled through the test section at a low velocity (maximum 29 ft/sec) by means of a small blower at the exhaust end of the tunnel. The test section is lit with floodlamps from the top and bottom. Smoke is generated in a reservoir, which is located in a compartment beneath the wind tunnel. Oil in the reservoir saturates a wick wrapped around a wire heating element that vaporizes the oil. An air tube, which originates from the downstream end of the blower, forces air through the reservoir and picks up the oil producing a fine smoke. The reservoir is connected to a streamlined feeder pipe that stands vertically in the middle of the flow at the upstream end of the wind tunnel test section. This feeder pipe spans the height of the test section and includes 25 small tubes spaced 3/4 inch apart that protrude from the downstream side of the feeder pipe. Smoke emerges from these small tubes and enters the main airstream, so that at the test section entrance an observer sees the flow streamlines as discrete narrow bands of white smoke. Various models may be mounted in the test section and the resulting flow patterns formed by the streaklines can be observed (or recorded by a camera). The flow velocity is kept low so that the smoke particles in the freestream will stay in layers or lamina and maintain their identity; smoke in turbulent flow tends to dissipate and makes observation difficult.
Most of the time young people are not patient to work at slow speed and prefer the higher speeds, but in this video there are interesting effects which are not seen so clearly at higher speeds. In one of your other videos , I commented about the fact that there are two types of vortexes generated, some are of the types that have their axis parallel with the flow as those on the wing tips of a wing while the others are those whose axis are parallel with the trailing edge or leading edge of the wing. 1. At 0:21, when the flow is switched off and the velocity of air is slow, the vortexes which are long and stretched and parallel with the flow are so easy to see, including their rotation. Now it is well known that even an flat oscillatory planar motion can be attributed tow vortexes rotating in opposite direction. A sinusoidal or a cosine oscillation which may be seen as a flat function is attributed to two vortexes or helix rotating in opposite direction. The beauty of fluid mechanics rather than electromagnetic " fluid " is that one can see it all before our eyes. Again, at 0:21 the long stretched helix are easily seen growing till they destroy themselves. At 0:23 the relation has introduce an action where the growing long stretched vortex is seen being sucked back to form a rotation whose axis is at right angles with the flow. At the lower velocity of the flow, the volume of dormant or stagnant fluid on top of the wing and being carried with it seem to warrant more observations as it could prove that a bubble of low pressure air as long as it is sealed can also produce lift. It seems that the long stretched vortexes parallel with the flow do retain the sealing of the low pressure zone above the wing and the other type of vortexes with their axis parallel to the trailing and leading edge do puncture the low pressure bubble above the wing. The puncture of the low pressure zone above the wing is due to the lower vortex behind the trailing edge pumping high pressure air with it due to viscosity and this is caught up by the upper vortex from the leading edge and the meshed part between the two vortexes pump up high pressure fluid on the top surface of the wing. The action is fast but very clear in your experiment. As for the oscillations that occur at high angle of attack they are similar in nature to what happened in you experiment when you had a cylinder in the flow. It is a pity that due to the narrow design of the wind tunnel the puncturing of the low pressure zone above the wing due to the wing tip vortexes having their axis at right angle to the flow cannot be seen, but the puncturing of the sealed low pressure bubble above the wing is easily seen at 2:10 Full marks for your work, but when conducting such research one should move from one action to another in a slow manner as I am afraid you did move too fast and missed out on some beautiful patters which would have been recorded for prosperity. Youth is a wonderful era in out life, but depth is something that you cannot see at first, but when they see what depth they could visualise , then they would take it easier and being gentle in movements would permit higher and deeper details to be recorded. Still well done and I wish I had more space at my home to build one of these wind tunnels.
Great insight! I’m at the first year of aerospace engineering and have t yet started fluid dynamics. Are you an engineer? What tips would you give to a student?
@@yuyy8565 be prepared for 2nd year, idk how it is with your uni but try your best to pay attention to lectures to understand key concepts especially aerodynamics and abstain from taking notes (unless the lecture isn't recorded). Attempt all worksheets given by the lecturers and try to get the best out of seminars and tutorials, when it comes to lab reports immediately start computing the data, obtaining the graphs and note down your observations as you wouldn't want to do this last minute of course. You can however do the discussions like a short period before the deadline in GOOD TIME but the data you gathered must be done, most importantly stay motivated throughout the course and enjoy it. I assume you'll also be taught what mechanical engineers are taught such as beams and thermodynamics. This is my advice which you can take or not take but I've given it and edit: You can take notes after the lecture is done but don't spend too much time as you need to spend this time on other modules. All the best,
Excellent just what I was looking for for my aircraft on cruise and approach mode. In cruise I have 6deg of reflex on the flaps and this gives the aircraft a slight one-up attitude and a 5 knot increase in speed. On approach with 35deg flap the aircraft is nose down so seeing the flow there too was good.
Some points to observe: The speed considered in the real situation is generated by the aircraft and those air flow behaviors showed in lab only represents parts of scenario. Properly the situation when the wings keep their horizontal position at enough engine power combined or not with flaps oscillatings.
Slightly upside down, needs a negative void on the bottom to move the vortex down Fibonacci is like an arrow, the upward curve points upward, all surfaces of the wing and fuselage engine housing, everything made in this pattern, it all produces lift exponentially .. then add an engine
Awesome video ! Do you have by any chance a video where the shharp trailing edge hits the ariflow first and the round leading edge leaves the airflo last? It would be of great use to demonstrate our engineering department that they are - at my point of view - wrong into mounting the spoiler at the front of our roofracks with a sharp edge as a leading edge and the round edge as a trailing edge. Granted; the spoiler's purpose is to create smoother airflow over the roofrack beams and not to create lift in either negative or poisitive sense. But still, arent all airfoils supose to be mounted with round ledading edge and sharp trailing edge?
not really that expensive, you can make your own, the smoke and the air is been recycled back and forth, buy a fish tank and start there, put the fish tank with all its components already installed and you good to go, you can get all of the parts from eBay and Amazon for cheap.
@ time stamp 2:27 China Airlines flight #006 can tell you how that decent feels like 😂. They exceeded 5 G's over a simple 1 engine failure it became a vomit comet 😂.
The authors have two wrong scientific approaches: researching the creation of Lift force and Low pressure at upper side of the wing, relative to the ground surface and Earth. I explain the aerodynamic cavitation and existence of Lee side aerocavern, and creation of Aerodynamic force.
yes, we were Aerospace Engineering students at Georgia Tech. This was done for our fluid dynamics lab class. We did not construct the wind tunnel. We were there to observe the behavior of airfoil in the flow field.
The issue with this video for a layman, is they don't show the effect of what they are doing in real airplane. Difficult to understand for a Non-physics person.
For passing air through buildings to reduce CO2 we have to build the building in cities in such a way where air can pass and circulate throughout the city.
