  The correlation between the harmonic flow and the transverse flow in
relativistic heavy ion collisions is calculated in the hydrodynamic model. The
partial correlation coefficient, corrected for fluctuations of multiplicity, is
compared to experimental data. Estimators of the final transverse and harmonic
flow are used to predict the value of the correlation coefficient from the
moments of the initial distribution. A good description of the hydrodynamic
simulation results is obtained if the estimator for the final transverse flow,
besides the most important transverse size and entropy, includes also the
eccentricities.
