Standing waves in air

Standing waves in a open and half-closed pipes. Also see standing waves in a flute, traveling waves in air, and more related figures in the Music category.

Pressure and displacement

Closed pipe

Half-open pipe

Open pipe

Edit and compile if you like:

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% Author: Izaak Neutelings (December 2020)
% http://hyperphysics.phy-astr.gsu.edu/hbase/Waves/standw.html
\documentclass[border=3pt,tikz]{standalone}
\usepackage{amsmath}
\usepackage{etoolbox} % ifthen
\usepackage{tikz}
\usetikzlibrary{arrows.meta} % for arrow size
\tikzset{>=latex} % for LaTeX arrow head
\colorlet{xcol}{blue!70!black}
\colorlet{vcol}{green!60!black}
\colorlet{Pcol}{orange!80!black}
\colorlet{dense air}{Pcol!70!red!60}
\colorlet{thin air}{brown!10}
\colorlet{myred}{red!65!black}
\tikzstyle{vvec}=[->,vcol,very thick,line cap=round]
\tikzstyle{wood}=[very thick,brown!70!black]
\tikzstyle{Pline}=[Pcol,very thick,line cap=round]
\def\tick#1#2{\draw[thick] (#1) ++ (#2:0.1) --++ (#2-180:0.2)}
\tikzstyle{myarr}=[xcol!50,-{Latex[length=3,width=2]}]
\begin{document}
% STANDING WAVE
\begin{tikzpicture}
  \message{Standing wave plot...^^J}
  \def\lam{2.0}      % wavelength
  \def\n{2}          % harmonic
  \def\L{\n*\lam}    % length
  \def\ymax{0.85}    % y maximum
  \def\xmax{1.02*\L} % x maximum
  \def\A{0.80*\ymax} % amplitude
  \def\D{1.20*\ymax} % pipe diameter
  \def\s{2.45*\ymax} % shift
  \def\N{1200}       % number of points
  %\def\N{500}        % number of points
  
  % DISPLACEMENT
  \foreach \i [evaluate={\x=(\i-0.75)*\lam;}] in {1,...,\n}{
    \draw[myarr] (\x,0.15*\A) --++ (0,0.65*\A);
    \draw[myarr] (\x+\lam/2,-0.15*\A) --++ (0,-0.65*\A);
 
 
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