The paper reports on the investigation of the flow and flame front dynamics in a premixed conical methane/air flame perturbed by an acoustic field. The investigation is carried out by using stereoscopic particle image velocimetry and planar laser-induced fluorescence of HCHO to measure simultaneously the instantaneous velocity field and flame front location in the axial plane. The optical techniques provided information about local velocity and velocity gradients, stretching and curvature of the flame front. Flow conditions when the flame is covered from the top by a cooled metallic flat plate are also considered. It is found that the flow and flame front lose axial symmetry when the obstacle is present because of disruption of the global instability mechanism of the combustion products plume driven by bouncy force.