GitHub - OpenFAST/openfast: Main repository for the NREL-supported OpenFAST whole-turbine and FAST.Farm wind farm simulation codes. This might have wind turbine airfoil data.
https://forum.openscad.org/UIUC-Airfoil-Coordinates-Database-td20264.html
https://royalsocietypublishing.org/doi/10.1098/rsif.2019.0118 A chordwise offset of the wing-pitch axis enhances rotational aerodynamic forces on insect wings: a numerical study
Michael Dickinson (CalTech) 1: How Flies Fly: Lift
Michael Dickinson (CalTech) 2: How Flies Fly: Power
Michael Dickinson (CalTech) 3: How Flies Fly: Control
1 Like
Nice: A biologist tries to explain âliftâ. His âBernoulliâ explanation is long discredited as not sufficient even to explain lift from a bird or airplane wing. There is just not enough lift generated for flight by the mere difference in transit time from top to bottom, and that includes the fact that the air flows back, over the top, much faster than the wingâs forward motion.
I only watched the first video - one could waste all day listening to this crapola. I hope to do a video on the correct reason wings fly, which I understand, but which ânobody has figured out yetâ according to âauthoritiesâ such as Scientific American:
He has studied and has done experiments on how insects fly for the last three decades. This is an excellent talk. He gives short and very clear overviews of the relevant theories applicable to his research and shows the results of his and othersâ experiments. He shows high speed footage, force measurements, and nice simulations of results. His research has furthered our understanding of insect flight with the help of novel experimental setups. I recommend watching the full video, and the others too.
The bit on leading edge vortices being important for rotors and insect flight but quickly dissipating in translational motion was new to me, for example.
Wow I havent seen that openscad foil database. Curious if it works with my bladegen codeâŠ
Oh yeah, I was paying attention - some nice stuff. Only thing is, like I saw David Attenborough do in another video about pterosaurs, he just recites the Bernoulli myth that âthe reasonâ for lift is faster air on the top surface. That has been debunked since forever. Calculations alone show that air velocity alone cannot produce sufficient low pressure to explain the amount of lift generated by an airfoil. This is the problem with âscienceâ: Outdated wrong explanations live on, enjoying habitual and unquestioning âlegitimacyâ, while in reality, with wings being used all over the world for over a century, âscienceâ still canât explain how they work. This is funny, and it leaves the door wide open for people who CAN explain how it works to do so. Aside from that, of course I could watch that sort of stuff all day, but have other things to do.
Not related to your comment, but clicking through the references gets you here for example: UIUC APA - LSATs Airfoils Tested and then test data and commentary for the SG6040 airfoil, which I noticed is thicker than most of the rest: https://m-selig.ae.illinois.edu/uiuc_lsat/Low-Speed-Airfoil-Data-V3.pdf
For AWE I guess the sailplane airfoils make most sense to look into, or perhaps the thicker ones for their strength.
For designing your own wind turbine blades, which I was looking into, QBlade seems to make sense. That does allow importing of .dat files: Optimized Wind Turbine Blade Design using QBlade.
1 Like
Or slope soaring / racing airfoils. Browsing UIUC Airfoil Data Site and then searching for Jochen for example gives this:
It is indeed interesting to survey the gamut of airfoil choices that abound from every direction. However you may also be familiar with the term ârearranging the deck chairs on the Titanicâ. Or maybe a discussion of what music the band should play as the Titanic sinks. In my limited experience, getting too far off intro the weeds in such details as a specific choice of airfoils is best reserved for fine-tuning a system that is known to work well, rather than something to fixate on when trying to develop a configuration that simply works well. If it looks like an airfoil, walks like an airfoil, quacks like an airfoil, and, hopefully, flies like an airfoil, it will probably work fine for whatever you are working on. Just sayinâ⊠
1 Like
NEW R&D Sessions Ports of the Future - Contributing to a greener transport sector - YouTube
These projects are discussed in the above:
The Magpie project includes a blue-water electrical charging buoy and an autonomous electrical barge for example. Current Direct is about large swappable batteries for ships.
Yes I totally agree. Airfoils is probably the wrong place to start, but: Some AWE groups are looking into multifoil wings, and these are complex machines that do require going somewhat in depth to get decent performance. But for as long as a larger single foil wing is sufficient, it should be the first choice
All good arguments but
Meh, Just let the massive parameter set brains of computers do the designing for us instead
I donât think it came up with anything new but - still cool
Also
Thanks for the How flies fly videos⊠(Wow) Rotors are definitely better was my reading of it.
Oh and yes you can see from my search box I went for the fancy new 3d printer -yay- itâs fast
1 Like
The main determining factor for power from a given wind turbine rotor is blade length (which determines swept area). Iâll give you some inside info on blades:
- If your choice of airfoils offers less lift, then it will slow the air going through the rotor less, increasing the airflow speed, which will then bring more power to the rotor. This means if you get a wind turbine rotor anywhere âin the ballparkâ of being a decent rotor, it will self-adjust toward the sweet-spot of energy capture.
- If your rotor has a higher solidity (wider blades/excessive chord), then you donât need a high lift airfoil, because you have more airfoil out there than necessary, so a lower-lift, more streamlined airfoil (that offers less drag) will actually be a better choice.
So, really, once you know what youâre doing (which most people donât) if you like the look of your airfoil, it is probably a good choice. If it looks pretty, it should work pretty well.
It does help to look at a few hundred airfoils, but after than, you should be familiar with what look offers what attributes, so just make one that looks nice to you and it will work great.
Twist and taper are also important parameters. Neither are absolutely necessary for decent performance though. The old 10 kW Bergey turbine here uses pultruded blades with a constant pitch and chord, no twist or taper, and it works well, but gets noisy at high speeds with a way-too-wide and too-steep airfoil at the tip, but again, if you get it âin the ballparkâ the machine will self-adjust to extract good power.
1 Like
OK but if he starts out blithely mentioning the discredited Bernoulli explanation for lift, as a reflexive starting point, how much does he really understand about any sort of lift? The leading edge vortex version of lift was mentioned by, of all people, Dave Santos, a few years back, explaining the lift of delta kites and supersonic fighter jets at high angles of attack. So this might be good information, but it might also only be a partially-correct explanation. It reminds me of cheap balsa-wood model airplanes with completely thin, planar wings - they seem to fly just fine. Iâm guessing they are so light for the comparatively large amount of surface area that they fly just fine due to low loading of an âairfoilâ, at such a low angle of attack, that doesnât even need an airfoil shape to function. That is similar to a wind turbine blade with high solidity (large chord length or large number of blades) not needing a high camber, thick airfoil to get good performance.
This is why AWE remains at a perpetual standstill: Rather than everyone simply knowing how great rotors are after thousands of years of refinement, they think they âdiscoverâ the better qualities of a rotor from watching some guy guess at how insect wings work, when the low Reynolds numbers insect wings operate in makes them almost irrelevant to wind energy. Or they try to force their kites to fly in a circle, wasting huge amounts of energy in the process, then just give up on wind energy.
Here is a time-stamped link on it writing code for example. I would also definitely use it to do first research on a topic as a sort of untrustworthy encyclopedia to get me started. Your prompts were perhaps a bit broad.
Or if you want to apply it to AWES workâŠ
Can you suggest C++ code to control a motor using VESC in position control mode based on the rotational position of a networked ESP32 with an IMU
Sure! Here is an example of how you can control a motor using VESC in position control mode based on the rotational position of a networked ESP32 with an IMU:
Copy code
#include "VescUart.h"
#include "esp32-hal-i2c.h"
#include "MPU6050.h"
// Create an instance of the VESC UART library
VescUart UART;
// Create an instance of the MPU6050 library
MPU6050 accelgyro;
// Set the I2C address of the ESP32
#define I2C_ADDRESS 0x68
// Set the communication parameters for the VESC
#define VESC_UART_BAUD 115200
#define VESC_UART_PORT UART_NUM_1
// Set the target position for the motor
#define TARGET_POSITION 0.5
void setup() {
// Initialize the I2C bus
Wire.begin(I2C_SDA, I2C_SCL);
// Initialize the VESC UART connection
UART.begin(VESC_UART_BAUD, VESC_UART_PORT);
// Initialize the IMU
accelgyro.initialize();
}
void loop() {
// Read the current rotational position of the ESP32 from the IMU
int16_t ax, ay, az;
int16_t gx, gy, gz;
accelgyro.getMotion6(&ax, &ay, &az, &gx, &gy, &gz);
// Set the target position of the motor based on the ESP32's current rotational position
UART.set_duty_cycle(TARGET_POSITION);
}
This code uses the VescUart library to control the VESC and the MPU6050 library to read the rotational position of the ESP32 from the IMU. The motor will be set to the target position based on the ESP32âs current rotational position.
Not a bad start
This is kinda the opposite of slow chat
Ok, after a few enquires. Speaking to these guys
https://e-magnetsuk.com/ about customer magnets.
I might just be able to get the magnets I want made as a custom?
What to know if you guys know of other suppliers? That do 16-18mm dia. Spherical or oval magnets? I just got qoute ÂŁ50 for 10 custom magnets. however? they did mention its cheaper in bulk 100-250 pieces bulk prices would be something similar? As I can be a blind in the procurement of such items any suggestions?
No. Apparently they have or are able to source the magnets youâre looking for. I think the price you were quoted is reasonable. There are cheaper websites though, although I donât know if those carry spherical magnets.
You should invest some time into learning Fusion 360 or SketchUp or something so you can better visualize for yourself and communicate to others what youâd like to make.
1 Like