import vtk  
import numpy
import vtk.numpy_interface.dataset_adapter as dsa

output = dsa.WrapDataObject(self.GetOutputDataObject(0))
# **** set properties panel Output Dataset Type to vtkTable

colNames = [ 'simulation', 'v0 (m/s)', 'k (%)' ]
col0     = [ 'm01-sim001', 'm01-sim002', 'm02-sim001' ] 
col1     = [ 1, 2, 3 ]
col2     = [ 0.01, 0.02, 0.03 ]

output.RowData.append(col0, colNames[0]); # *** fails on string valued array
output.RowData.append(col1, colNames[1]); # int valued array works ok
output.RowData.append(col2, colNames[2]); # float valued array works ok