#!/usr/local/bin/ruby -d

include Math


amp=1.0
#y_peak=2.0*PI/2.0
y_peak=0.3
t=2.0*PI

zeta = Array.new(1000)

print "#y, zeta(y)\n"

100.times do |i|
  y_i = 2*PI/100.0*i #i番目のy座標値
  zeta[i] = 0.0    #i番目のy座標における渦度の値
  if y_i < y_peak
    zeta[i] += 2*amp*(y_i)/y_peak-amp
  else
    zeta[i] += 2*amp*(y_i-t)/(y_peak-t)-amp
  end
  print "#{y_i}, #{zeta[i]} \n"
end