def write_outflow(file_name, outflow):
    """Write the outflow values to a file.
    """
    fobj = open(file_name, 'w')
    header = outflow.keys()
    for head in header:
        fobj.write('%20s' % head)
    fobj.write('\n')
    for lineno in range(len(outflow[head])):
        for head in header:
            fobj.write('%20.17f' % outflow[head][lineno])
        fobj.write('\n')
