This is one I like from my thesis. It illustrates the predicted boundaries for boundary layer transition mechanisms on a cylindrical afterbody at incidence:
- free shear-layer instability,
- ttachment-line instability,
- cross-flow instability,
- streamwise-flow instability.
\documentclass[border=5pt]{standalone}\usepackage{pgfplots}\pgfplotsset{width=7cm,compat=1.8}%% free shear-layer instability (fsli)\pgfmathdeclarefunction{fsli}{1}{%\pgfmathparse{ tan(#1)/( cos(#1)*( 1 + 3.3*((tan(#1))^2) ) ) }%}%%%% attachment-line instability (ali)\pgfmathdeclarefunction{ali}{1}{%\pgfmathparse{ 1.1*tan(#1)*(1/cos(#1)) }%}%%%% cross-flow instability (csi)\pgfmathdeclarefunction{csi}{1}{%\pgfmathparse{ 0.145*( ( 1 + 3.3*(tan(#1))^2 ) / sin(#1) ) }%}%%%% streamwise-flow instability (sfi)\pgfmathdeclarefunction{sfi}{1}{%\pgfmathparse{ 4 }%}%%%% piecewise function (combining ali, csi and sfi)\pgfmathdeclarefunction{alicsisfi}{1}{%\pgfmathparse{%(and( #1>=1 , #1<=25.78) * ( ali(x) ) +%(and( #1>25.78 , #1<=70.00) * ( csi(x) ) +%(and( #1>70.00 , #1<=89.99) * ( sfi(x) ) %}%}%\begin{document}\begin{tikzpicture}% set style options for annotations with pins (see bottom of tikzpicture)\tikzset{%every pin/.style={draw=none,fill=none,%rectangle,rounded corners=0pt,font=\scriptsize}}\begin{semilogyaxis}[%%view={0}{90},width=0.50\linewidth,height=0.75\linewidth,%scale only axis,axis on top=false,axis lines*=box,%xmin=0, xmax=90,xtick={0,10,20,30,40,50,60,70,80,90},xlabel={\raisebox{0pt}[\height][\depth]{$\alpha$ (deg)}},%ymin=0.1, ymax=10,ytick={0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0,2,3,4,5,6,7,8,9,10},yticklabels={0.1,0.2,{},0.4,{},0.6,{},0.8,{},1.0,2,{},4,{},6,{},8,{},10},ylabel={\raisebox{0pt}[\height][\depth]{$R_D \times 10^{6}$}},]%% fsli (start stacking)\addplot[domain=1:89.99,samples=225,draw=none,fill=none,mark=none,stack plots=y]{ fsli(x) };%%% stack difference between alicsisfi (upper) and fsli (lower) curves on top of fsli and fill area\addplot[domain=1:89.99,samples=225,draw=none,fill=black!10,stack plots=y]{ max( alicsisfi(x) - fsli(x) , 0 ) } % area above fsli and below alicsisfi\closedcycle;%% fsli, alpha = [1 , 89.99]\addplot[domain=1:89.99,samples=225,solid,line width=0.8pt,draw=black,mark=none]{ fsli(x) };%% ali (1), alpha = [1 , 25.78]\addplot[domain=1:25.78,samples=62,solid,line width=0.8pt,draw=black,mark=none]{ ali(x) };%%% ali (2), alpha = [25.78 , 89.99]\addplot[domain=25.78:89.99,samples=163,dashed,draw=black,mark=none]{ ali(x) };%% csi (1), alpha = [1 , 25.78]\addplot[domain=1:89.99,samples=62,dashed,draw=black,mark=none]{ csi(x) };%