  We carry out two-dimensional magnetohydrodynamic (MHD) simulations of an
ensemble of Alfv\'enic fluctuations propagating in a structured, expanding
solar wind including the presence of fast and slow solar wind streams. Using an
appropriate expanding box model, the simulations incorporate the effects of
fast-slow stream shear and compression and rarefaction self-consistently. We
investigate the radial and longitudinal evolution of the cross-helicity, the
total and residual energies and the power spectra of outward and inward
Alfv\'enic fluctuations. The stream interaction is found to strongly affect the
radial evolution of Alfv\'enic turbulence. The total energy in the Alfv\'en
waves is depleted within the velocity shear regions, accompanied by the
decrease of the normalized cross-helicity. The presence of stream-compression
facilitates this process. Residual energy fluctuates around zero due to the
correlation and de-correlation between the inward/outward waves but no net
growth or decrease of the residual energy is observed. The radial power spectra
of the inward/outward Alfv\'en waves show significant longitudinal variations.
Kolmogorov-like spectra are developed only inside the fast and slow streams and
when both the compression and shear are present. On the other hand, the spectra
along the longitudinal direction show clear Kolmogorov-like inertial ranges in
all cases.
