From 836ae22bcb2a57c3c5753c0b3146c1e7bcb47e27 Mon Sep 17 00:00:00 2001
From: Thomas Lambert <t.lambert@uliege.be>
Date: Mon, 13 Feb 2023 11:48:28 +0100
Subject: [PATCH] feat(input): update Airfoil.extrapMethod
---
contents/user-input.tex | 36 +++++++++++++++++++++++++++---------
1 file changed, 27 insertions(+), 9 deletions(-)
diff --git a/contents/user-input.tex b/contents/user-input.tex
index c743740..67e09ce 100644
--- a/contents/user-input.tex
+++ b/contents/user-input.tex
@@ -300,16 +300,34 @@ structures (\ie \lst{Airfoil(1)}, \lst{Airfoil(2)}, \dots).
present and usable in your installation.
}
-\describeOption{Airfoil.extrap}{}{\lst{true, false}}{
- Extrapolate the polars from \lst{Airfoil.polarFile} over the complete range of
- angles of attack ([-180, 180] deg). Although this extrapolation is not ideal,
- it allows for the computation of sections that are at very large/low angles of
- attack. This is particularity useful when doing a sweep of operating
- conditions.
+\describeOption{Airfoil.extrapMethod}{}{See below}{
+ \danger \, \textit{Only used when \lst{Airfoil.polarType='file'}}.
+
+ Extrapolation method to use in order to recover the lift and drag coefficients
+ from incomplete polars.
+ Possible choices are:
+ \begin{itemize}
+ \item \textbf{none}: no extrapolation allowed. Will return an error if the
+ solution requires the calculation of an angle of attack outside of the
+ range provided by the user.
+ \item \textbf{spline}: spline extrapolation if angle of attack is outside
+ the range of angles given in the input polar. Strongly discouraged.
+ \item \textbf{viterna}: Extrapolation of the polars over the entire range of
+ angles of attack according to Viterna formulas~\ref{}. Although this
+ is not perfectly correct (as it is the case for any extrapolation), this
+ option is the one that is closer to the reality. This is particularity
+ useful when doing a sweep of operating conditions and many off-design
+ points must be studied.
+ \end{itemize}
+ Note that convergence may be more trickier to achieve in some edge cases and
+ off-design analysis with the low-order extrapolation methods.
+ In operation at the design point, extrapolation should not be required at all
+ (as long as the polars are provided for values between the minimum lift and
+ the stall point).
}
\describeOption{Airfoil.clPoly}{deg$^{-1}$}{Vector}{
- \danger \, \textit{Only used when \lst{Mod.polars='manual'}}.
+ \danger \, \textit{Only used when \lst{Airfoil.polarType='polynomial'}}.
Coefficients for the polynomial form of the lift coefficient, $C_l$.\\
The vector should be in the form $[p_1, p_2, ..., p_n]$ to represent the
@@ -319,9 +337,9 @@ structures (\ie \lst{Airfoil(1)}, \lst{Airfoil(2)}, \dots).
}
\describeOption{Airfoil.cdPoly}{deg$^{-1}$}{Vector}{
- \danger \, \textit{Only used when \lst{Mod.polars='manual'}}.
+ \danger \, \textit{Only used when \lst{Airfoil.polarType='polynomial'}}.
- Same as \lst{Blade.Airfoil.clPoly}, but for the drag coefficient.
+ Same as \lst{Airfoil.clPoly}, but for the drag coefficient.
}
--
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