Helmholtz resonators (HR) have been used to mitigate the low-frequency pressure pulsation phenomenon in Göttingen style low-speed open-jet wind tunnels (OJWT). For lack of an efficient predictive tool, the deployment design of an HR usually depends on a scale model method. A 3-D computer simulation is foreseeably very costly computationally to resolve the complex flow-acoustics coupling phenomenon in a physical wind tunnel airline geometry. Recently, an innovative computational strategy was proposed by the authors. It was shown that the challenging flow physics problem could be tackled very economically and the long-observed phenomenon of airspeed dependent intensification of pressure pulsation could be unequivocally revealed. The authors have now expanded the same efficient predictive method to study the mitigation effect of HR on the pressure pulsation phenomenon. The condition of pure acoustic response with quiescent mean flow is studied first in a long looped duct. The model produces an instructive resonance condition for comparing to the result of HR installation on the OJWT airline. Based on the result of acoustic resonance, the study proceeds to the wind-on simulation that includes installation of HR at different locations along the airline.