We use singular value decomposition techniques to generalize the
wavelet transform modulus maxima method to the multifractal
analysis of vector-valued random fields. The method is calibrated
on synthetic multifractal 2D vector measures and monofractal 3D
fractional Brownian vector fields. We report the results of some
application to the velocity and vorticity fields issued from 3D
isotropic turbulence simulations. This study reveals the existence of
an intimate relationship between the singularity spectra of these two
vector fields which are found significantly more intermittent than
previously estimated from 1D longitudinal and transverse velocity
increment statistics.