Question

我有一个gnuplot问题，我是初学者，我相信他们可以帮助我... 我正在尝试重现此链接的图形（图4.5，https://homepages.see.leeds.ac.uk/~amt6xw/Distance%20Learning/CFD5050TURB/node22.html，但不幸的是，我没有成功。图表仅绘制了一条曲线（代码中的第一条曲线），而我编写的最后两条曲线却出现了错误（图例中出现了很多线，但没有图表），您能帮我吗？

代码也仅在“ set trange [0:25]”行中搜索参考，这使得无法绘制其他图形，我需要学习如何确定变量的多个“范围”。

reset

## CONFIGURAÇÕES DO ARQUIVO DE SAÍDA (http://www.gnuplotting.org/output-terminals/):

set terminal pngcairo size 800,600 enhanced font "Verdana,10"
set output "yPlus.png" 

# AJUSTE DAS MARGENS DO CONTEÚDO NO INTERIOR DA TELA:
# GUIA: l = left; r = right; t = top; b - bottom

set lmargin 7.5
set rmargin 3.5
set bmargin 3.5
set tmargin 1

set grid

# LEGENDAS LATERAIS:

set xlabel "r+" font "Verdana,10"
set ylabel "<u_{z}>+" font "Verdana,10"

# RANGE DO EIXO Y:

set parametric
set trange [0:25]

# RANGE DO EIXO X:

set logscale x 
set xrange [*:1000]
set format x "10^{%L}"

# LEGENDA DO GRÁFICO:

set key ins vert
set key top left
set key box

## CONFIGURAÇÕES DOS GRÁFICOS:

# SPALDING'S LAW OF THE WALL (https://homepages.see.leeds.ac.uk/~amt6xw/Distance%20Learning/CFD5050TURB/node22.html) (- 1/24*((k*t)**4)): 

# Karman's constant (k = 0.4):
k = 0.4187

# ...for a smooth wall (A = 0.1108):
E = 9.0

f(t) = t + 1/E*(exp(k*t) - 1 - k*t - 1/2*((k*t)**2) - 1/6*((k*t)**3))

plot f(t),t title "Spalding's Law of the Wall" with lines linetype -1

# LOGARITHIMIC OVERLAP:

g(y) = 1/k*log10(E)*y

plot for [y = 35:350] g(y),y title "Logarithimic overlap" with lines linetype -1

# LINEAR SUBLAYER:

plot for [t = 0:20] t,t title "Linear Sublayer" with lines linetype -1

Answer 1

如果要在单个图/图中绘制所有内容，则只需调用一次plot命令。另外，为了对同一图中的不同依赖项使用不同的“范围”，可以如下所示手动重新缩放t变量。例如，由于t从0到25，scale1函数将其按预期转换为[35; 350] ...

set trange [0:25]

f(t) = t + 1/E*(exp(k*t) - 1 - k*t - 1/2*((k*t)**2) - 1/6*((k*t)**3))

g(y) = 1/k*log10(E)*y

scale1(t) = t*315./25 + 35
scale2(t) = t*20./25

plot \
    f(t),t title "Spalding's Law of the Wall" with lines linetype -1, \
    g(scale1(t)),scale1(t) title "Logarithimic overlap" with lines linetype -1, \
    scale2(t),scale2(t) title "Linear Sublayer" with lines linetype -1

尝试在Gnuplot中绘制多个图形时出错

1 个答案: