Bulk viscosity effects in event-by-event relativistic hydrodynamics

Bulk viscosity effects on the collective flow harmonics in heavy-ion collisions are investigated, on an event-by-event basis, using a newly developed 2 + 1 Lagrangian hydrodynamic code named V-USPHYDRO, which implements the smoothed particle hydrodynamics algorithm for viscous hydrodynamics. A new formula for the bulk viscous corrections present in the distribution function at freeze-out is derived, starting from the Boltzmann equation for multi-hadron species. Bulk viscosity is shown to enhance the collective flow Fourier coefficients from v(2)(p(T)) to v(5)(p(T)) when p(T) similar to 1-2.5 GeV, even when the bulk viscosity to entropy density ratio, zeta/s, is significantly smaller than 1/(4 pi).