# The Blasius equation in Python

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 May 3, 2011, 14:49 The Blasius equation in Python #1 New Member   Join Date: May 2011 Posts: 1 Rep Power: 0 Hi everybody I'm writing a script in Python to solve the Blasius equation but it does not work, numerical results does not match with data I've seen in fluid mechanics books. Please anyone could help me? Thank you very much Script is import sys, pylab, numpy from pylab import * from numpy import * import matplotlib.pyplot as plt deta=0.0001 total=10 e = [] f = [] g = [] h = [] fvec=0; gvec=0; hvec=0.3219 etavec=0.0 while etavec <= 10: fvec = fvec + gvec * deta gvec = gvec + hvec * deta hvec = hvec -(1/2) * fvec * hvec * deta etavec = etavec + deta e.append(etavec) f.append(fvec) g.append(gvec) h.append(hvec) print etavec,fvec,gvec numpy.savetxt("blasius.dat", transpose((e,f,g,h)),delimiter=' ') pylab.figure() pylab.plot(e,g) pylab.plot(e,h) xticklines = getp(gca(), 'xticklines') yticklines = getp(gca(), 'yticklines') xgridlines = getp(gca(), 'xgridlines') ygridlines = getp(gca(), 'ygridlines') xticklabels = getp(gca(), 'xticklabels') yticklabels = getp(gca(), 'yticklabels') #lines1 = pylab.plot(e,f) lines2 = pylab.plot(e,g) lines3 = pylab.plot(e,h) #pylab.setp(lines1, color='b', linewidth=3.0) pylab.setp(lines2, color='r', linewidth=3.0) pylab.setp(lines3, color='k', linewidth=3.0) setp(xticklines, 'linewidth', 3) setp(yticklines, 'linewidth', 3) setp(xgridlines, 'linestyle', '--') setp(ygridlines, 'linestyle', '--') setp(yticklabels, fontsize='xx-large') setp(xticklabels, fontsize='xx-large') xlabel('$\eta$',fontsize=30) ylabel('$f(\eta) \quad \partial_{\eta} f(\eta) \quad \partial_{\eta \eta}f(\eta)$',fontsize=30) axis([0.0,10,-0.9,20.9]) #legend( (lines1, lines2, lines3), ('$\f(\eta)$', '$\partial_{\eta} f(\eta)$', '$\partial_{\eta \eta}f(\eta)$')) grid(True) pylab.show()