Calculate average wind velocity
I've got an anemometer to measure wind speed.
Its ratio is $50Hz = 15.5m/s$, so my Arduino counts pulses in 3100ms, which should give a count of $100 = 10m/s$.
I can display this on a dashboard on the wall, but I'm more interested in an average.
(I'm just using this for fun, I'm not controlling the traffic on a bridge or in an airport)
But what makes more sense?
I can count pulses for $(19*3.1) = 59.8 text{seconds}$ and divide by 190 to get an average for 1 minute.
Or the same for 10 minutes.
Or I could have a memory of the last p samples so I add the sample to a register, and divide with p, then at Tp subtract it from the register again, so I get a running average over the last minutes.
I could also take a weighted average of the current value and the current average as the next current average, which would emulate the charging and discharging of a capacitor. Something like
$$overline{V} = frac{V + (n-1)overline{V}prev}{n}$$
Or should I take into the account that energy of the wind is proportional to the speed cubed?
So 1 minute of 10m/s and 1 minute of 20 m/s have the same energy of
$$ sqrt[3]frac{10^{3} + 20^{3}}{2} approx 16.5 $$
average
asked yesterday
Lenne
1273
|
show 2 more comments
I've got an anemometer to measure wind speed.
Its ratio is $50Hz = 15.5m/s$, so my Arduino counts pulses in 3100ms, which should give a count of $100 = 10m/s$.
I can display this on a dashboard on the wall, but I'm more interested in an average.
(I'm just using this for fun, I'm not controlling the traffic on a bridge or in an airport)
But what makes more sense?
I can count pulses for $(19*3.1) = 59.8 text{seconds}$ and divide by 190 to get an average for 1 minute.
Or the same for 10 minutes.
Or I could have a memory of the last p samples so I add the sample to a register, and divide with p, then at Tp subtract it from the register again, so I get a running average over the last minutes.
I could also take a weighted average of the current value and the current average as the next current average, which would emulate the charging and discharging of a capacitor. Something like
$$overline{V} = frac{V + (n-1)overline{V}prev}{n}$$
Or should I take into the account that energy of the wind is proportional to the speed cubed?
So 1 minute of 10m/s and 1 minute of 20 m/s have the same energy of
$$ sqrt[3]frac{10^{3} + 20^{3}}{2} approx 16.5 $$
average
asked yesterday
Lenne
1273
1
The energy of the wind is proportional to the speed squared. The power of the wind is proportional to the speed cubed.
– Acccumulation
yesterday
So would it give more sense to calculate the RMS than the average?
– Lenne
yesterday
2
It depends on why you want an average. If you want to know how far a free-floating balloon might drift in an hour, you want average velocity. If you want to know how much electricity a wind turbine might generate in an hour, you want average power (I think--anyway not just average speed).
– David K
yesterday
What kind of average would be the right to determine if it was safe to cross a bridge in a storm?
– Lenne
yesterday
You might experiment with "exponential smoothing". It's easy to compute, flexible, and is often used to smooth time series. en.wikipedia.org/wiki/Exponential_smoothing
– awkward
yesterday
|
show 2 more comments
I've got an anemometer to measure wind speed.
Its ratio is $50Hz = 15.5m/s$, so my Arduino counts pulses in 3100ms, which should give a count of $100 = 10m/s$.
I can display this on a dashboard on the wall, but I'm more interested in an average.
(I'm just using this for fun, I'm not controlling the traffic on a bridge or in an airport)
But what makes more sense?
I can count pulses for $(19*3.1) = 59.8 text{seconds}$ and divide by 190 to get an average for 1 minute.
Or the same for 10 minutes.
Or I could have a memory of the last p samples so I add the sample to a register, and divide with p, then at Tp subtract it from the register again, so I get a running average over the last minutes.
I could also take a weighted average of the current value and the current average as the next current average, which would emulate the charging and discharging of a capacitor. Something like
$$overline{V} = frac{V + (n-1)overline{V}prev}{n}$$
Or should I take into the account that energy of the wind is proportional to the speed cubed?
So 1 minute of 10m/s and 1 minute of 20 m/s have the same energy of
$$ sqrt[3]frac{10^{3} + 20^{3}}{2} approx 16.5 $$
average
asked yesterday
Lenne
1273
I've got an anemometer to measure wind speed.
Its ratio is $50Hz = 15.5m/s$, so my Arduino counts pulses in 3100ms, which should give a count of $100 = 10m/s$.
I can display this on a dashboard on the wall, but I'm more interested in an average.
(I'm just using this for fun, I'm not controlling the traffic on a bridge or in an airport)
But what makes more sense?
I can count pulses for $(19*3.1) = 59.8 text{seconds}$ and divide by 190 to get an average for 1 minute.
Or the same for 10 minutes.
Or I could have a memory of the last p samples so I add the sample to a register, and divide with p, then at Tp subtract it from the register again, so I get a running average over the last minutes.
I could also take a weighted average of the current value and the current average as the next current average, which would emulate the charging and discharging of a capacitor. Something like
$$overline{V} = frac{V + (n-1)overline{V}prev}{n}$$
Or should I take into the account that energy of the wind is proportional to the speed cubed?
So 1 minute of 10m/s and 1 minute of 20 m/s have the same energy of
$$ sqrt[3]frac{10^{3} + 20^{3}}{2} approx 16.5 $$
average
average
asked yesterday
Lenne
1273
asked yesterday
Lenne
1273
asked yesterday
Lenne
1273
asked yesterday
Lenne
1273
asked yesterday
Lenne
1273
1273
1
The energy of the wind is proportional to the speed squared. The power of the wind is proportional to the speed cubed.
– Acccumulation
yesterday
So would it give more sense to calculate the RMS than the average?
– Lenne
yesterday
2
It depends on why you want an average. If you want to know how far a free-floating balloon might drift in an hour, you want average velocity. If you want to know how much electricity a wind turbine might generate in an hour, you want average power (I think--anyway not just average speed).
– David K
yesterday
What kind of average would be the right to determine if it was safe to cross a bridge in a storm?
– Lenne
yesterday
You might experiment with "exponential smoothing". It's easy to compute, flexible, and is often used to smooth time series. en.wikipedia.org/wiki/Exponential_smoothing
– awkward
yesterday
|
show 2 more comments
1
The energy of the wind is proportional to the speed squared. The power of the wind is proportional to the speed cubed.
– Acccumulation
yesterday
So would it give more sense to calculate the RMS than the average?
– Lenne
yesterday
2
It depends on why you want an average. If you want to know how far a free-floating balloon might drift in an hour, you want average velocity. If you want to know how much electricity a wind turbine might generate in an hour, you want average power (I think--anyway not just average speed).
– David K
yesterday
What kind of average would be the right to determine if it was safe to cross a bridge in a storm?
– Lenne
yesterday
You might experiment with "exponential smoothing". It's easy to compute, flexible, and is often used to smooth time series. en.wikipedia.org/wiki/Exponential_smoothing
– awkward
yesterday
1
1
The energy of the wind is proportional to the speed squared. The power of the wind is proportional to the speed cubed.
– Acccumulation
yesterday
The energy of the wind is proportional to the speed squared. The power of the wind is proportional to the speed cubed.
– Acccumulation
yesterday
So would it give more sense to calculate the RMS than the average?
– Lenne
yesterday
So would it give more sense to calculate the RMS than the average?
– Lenne
yesterday
2
2
It depends on why you want an average. If you want to know how far a free-floating balloon might drift in an hour, you want average velocity. If you want to know how much electricity a wind turbine might generate in an hour, you want average power (I think--anyway not just average speed).
– David K
yesterday
It depends on why you want an average. If you want to know how far a free-floating balloon might drift in an hour, you want average velocity. If you want to know how much electricity a wind turbine might generate in an hour, you want average power (I think--anyway not just average speed).
– David K
yesterday
What kind of average would be the right to determine if it was safe to cross a bridge in a storm?
– Lenne
yesterday
What kind of average would be the right to determine if it was safe to cross a bridge in a storm?
– Lenne
yesterday
You might experiment with "exponential smoothing". It's easy to compute, flexible, and is often used to smooth time series. en.wikipedia.org/wiki/Exponential_smoothing
– awkward
yesterday
You might experiment with "exponential smoothing". It's easy to compute, flexible, and is often used to smooth time series. en.wikipedia.org/wiki/Exponential_smoothing
– awkward
yesterday
|
show 2 more comments
0
active
oldest
votes
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3062210%2fcalculate-average-wind-velocity%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
0
active
oldest
votes
0
active
oldest
votes
active
oldest
votes
active
oldest
votes
Thanks for contributing an answer to Mathematics Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Some of your past answers have not been well-received, and you're in danger of being blocked from answering.
Please pay close attention to the following guidance:
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3062210%2fcalculate-average-wind-velocity%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
1
The energy of the wind is proportional to the speed squared. The power of the wind is proportional to the speed cubed.
– Acccumulation
yesterday
So would it give more sense to calculate the RMS than the average?
– Lenne
yesterday
2
It depends on why you want an average. If you want to know how far a free-floating balloon might drift in an hour, you want average velocity. If you want to know how much electricity a wind turbine might generate in an hour, you want average power (I think--anyway not just average speed).
– David K
yesterday
What kind of average would be the right to determine if it was safe to cross a bridge in a storm?
– Lenne
yesterday
You might experiment with "exponential smoothing". It's easy to compute, flexible, and is often used to smooth time series. en.wikipedia.org/wiki/Exponential_smoothing
– awkward
yesterday