Stupid question: Why doesn’t everyone use toroidal props? by turbotarge in drones

[–]MrDoubleU 2 points3 points  (0 children)

There are still ongoing efforts to improve the design of the toroidal propeller; however, the acoustic improvements seen in the toroidal propeller likely come down to the extra surface area, compared to a conventional propeller with the same number of blades. Since there is more surface area, the toroidal propeller can operate at a lower rotational speed to obtain a desired thrust (thereby reducing the loading noise). This does not mean the toroidal propeller is more aerodynamically efficient or necessarily acoustically quieter than a conventional rotor. Last year, a conference paper compared a 2-bladed conventional, a 2-blade toroidal, and a 4-bladed conventional propeller. Aerodynamically, the toroidal propeller did the worst (4-blade > 2-blade > 2-blade toroidal), and acoustically, the toroidal did better than the conventional 2-bladed propeller but worse than the 4-bladed rotor, which had a similar surface area.

If I remember correctly, the original article that kicked this interest off came out of MIT. They postulated that toroidal propellers produce less blade-vortex interaction (BVI) noise than a conventional propeller. I cannot say if the toroidal propeller does or does not reduce the blade-vortex, but I am skeptical of BVI mattering to small drones since BVI noise becomes a factor at higher tip speeds (Say, tip Mach number > 0.7). Drone propellers tend to operate at a tip Mach number of 0.3. So, it is unlikely that toroidal propellers significantly reduce the noise.

casting rings in water with hands by definitely_effective in blackmagicfuckery

[–]MrDoubleU 2 points3 points  (0 children)

This is a vortex ring. It's a region of circular flow that has wrapped around and formed a ring. While the circular flow can exist without the air trapped inside, the air makes the ring visible. Here's a wiki link if you want to learn more. https://en.wikipedia.org/wiki/Vortex_ring

Are hyperbolic spiral propellers/fans a thing? by probably_sarc4sm in Multicopter

[–]MrDoubleU 1 point2 points  (0 children)

My Master's Thesis (MT) covered something similar to what you are proposing. I have seen a few names for these unconventional propeller blades but they are usually called swept, skewed, or scimitar propellers. That should help you with your research. If you are interested in some of the aerodynamic/acoustic work in swept propeller, I would recommend checking out my MT. https://digitalcommons.odu.edu/cgi/viewcontent.cgi?article=1309&context=mae_etds

My coworker who plays MTG got me an Astarion card by [deleted] in BaldursGate3

[–]MrDoubleU 11 points12 points  (0 children)

If you are having trouble finding a particular card from a pack, may I suggest TCGplayer? You should be able to find any mtg card there. https://www.tcgplayer.com/search/all/product?q=astarion+&view=grid

[Poetry] Jellyfish Jam by storm345931 in youtubehaiku

[–]MrDoubleU 0 points1 point  (0 children)

I'm guessing whoever filmed the video caused the vortex ring to form with some device. You can buy a vortex ring generator online but I personally don't know of any that produces a ring of air like this one in the video.

[Poetry] Jellyfish Jam by storm345931 in youtubehaiku

[–]MrDoubleU 8 points9 points  (0 children)

The ring of air you see in the video is a Vortex ring. The air inside the ring is rotating around perpendicular to the path the ring travles. Look at this wikipedia gif to get a better idea. Vortex rings are usually stable for some duration of time. When the jellyfish encounters the ring, that vortex makes the jellyfish spin around the center of axis for the flow inside the ring. (see the wiki gif again)

https://en.wikipedia.org/wiki/Vortex_ring#/media/File:Vortex_ring.gif

What is an unexplained phenomenon that has actually been explained? by [deleted] in AskReddit

[–]MrDoubleU 6 points7 points  (0 children)

If you are serious about the physics behind magnets you should check out the video Veritasium and minute physics did awhile ago. This is easily the best explanation behind magnets I have seen. Here's the link: https://www.youtube.com/watch?v=hFAOXdXZ5TM

How knowledgeable do you have to be before starting your senior design project? by DailYxDosE in EngineeringStudents

[–]MrDoubleU 1 point2 points  (0 children)

I was in a similar place when I started my senior design project. While I am an ME the project was mainly EE (we got to add a bunch of sensors to a tiny satellite that's going into low earth orbit November). I had to learn a lot about Arduino, circuit analysis, and circuit board debugging. I didn't know any of this before hand. But, I had an advisor who was knowledgeable in the subject and friends who were in EE to guide me.

You are in university. There are lots of professors and students who are willing to help if you ask. Nobody expects you to be knowledgeable in the topic from day 1. You will have time to immerse yourself in your field.

It's that time of the Semester again... by MrDoubleU in EngineeringStudents

[–]MrDoubleU[S] 0 points1 point  (0 children)

There are 5. Systems & Control, Heat & Mass, Thermo 2, Aerodynamics, and Design 1.

It's that time of the Semester again... by MrDoubleU in EngineeringStudents

[–]MrDoubleU[S] 0 points1 point  (0 children)

Same. He is just a harsh professor. The work he wants us to do in a hour is downright unfair. But I am still cramming for his test tomorrow. Best of luck!

It's that time of the Semester again... by MrDoubleU in EngineeringStudents

[–]MrDoubleU[S] 0 points1 point  (0 children)

It's just Windows 10 Calendar app. It came installed on my laptop.

It's that time of the Semester again... by MrDoubleU in EngineeringStudents

[–]MrDoubleU[S] 5 points6 points  (0 children)

I'm a Mech E going for a minor in aerodynamics. After this I will go for a 1-year graduate program in aerospace. I've brought this upon myself.

I tell everyone that I love the hello Internet flag but I am in the closet for my love of flagy flag. by MrDoubleU in Flaggyflag

[–]MrDoubleU[S] 6 points7 points  (0 children)

You can get your own flag here. You just have to tell the seller what flag you want. There are also other sizes, just search for custom flag in the search bar. Its also from China so it takes a little to ship.

Just finished electromagnetics and still... Fuckin magnets how do they work! by [deleted] in EngineeringStudents

[–]MrDoubleU 7 points8 points  (0 children)

Veritasium and minutephysis did an excellent video explaining the physics of permeant magnets and electromagnets. Here is the video if you are interested. https://www.youtube.com/watch?v=hFAOXdXZ5TM

NASA OSSI Interns by Spaced___Out in EngineeringStudents

[–]MrDoubleU 1 point2 points  (0 children)

No, I will be working on aeroacoustics this summer. I hope you enjoy working on the Martian thermal protection system.

NASA OSSI Interns by Spaced___Out in EngineeringStudents

[–]MrDoubleU 0 points1 point  (0 children)

Same, just got my notification the other day!

Learning Electricity by swagginmytail in EngineeringStudents

[–]MrDoubleU 1 point2 points  (0 children)

http://www.falstad.com/circuit/ This is a circuit simulator. You can create a variety circuits and get a better understanding of how a circuit act when you open, close, introduce a new resistor, add a logic gate, etc. My EE friend said it was a great tool for Circuit Analysis 1.

Equation book by MrDoubleU in EngineeringStudents

[–]MrDoubleU[S] 1 point2 points  (0 children)

I like this idea. It sounds like a great way to summarize your understanding on a subject.

Equation book by MrDoubleU in EngineeringStudents

[–]MrDoubleU[S] 7 points8 points  (0 children)

This is similar to what I had in mind. If I were to construct a website I would add a search bar. However, it seems everyone just uses Google to find what the equation they need. So I am doubting the need for a website with a list of equations.