  The five-dimensional collective Hamiltonian based on the covariant density
functional theory is applied to investigate the observed tidal wave mode in the
yrast band of $^{102}$Pd. The energy spectra, the relations between the spin
and the rotational frequency, and the ratios of $B(E2)/\mathcal{J}(I)$ in the
yrast band are well reproduced by introducing the empirical $ab$ formula for
the moments of inertia. This $ab$ formula is related to the fourth order effect
of collective momentum in the collective Hamiltonian. It is also shown that the
shape evolution in the tidal wave is determined microscopically by the
competition between the rotational kinetic energy and the collective potential
in the framework of the collective Hamiltonian.
