In a combustion chamber, a gaseous or liquid fuel is injected as a secondary flow into a gaseous, channelized main flow. The main flow is directed to pass over a plurality of vortex generators (9) arranged side by side over the width or circumference of the channel (20) through which the flow passes. The height (h) of the vortex generators is at least 50% of the height (H) of the channel through which the flow passes or of that part of the channel associated with the vortex generators. The secondary flow is introduced into the channel (20) in the immediate vicinity of the vortex generators (9). Longitudinal vortices without any recirculation region are produced in the channel through which the flow passes by means of the new static mixer. Extraordinarily short mixing distances, with a low pressure loss at the same time, are thus achieved in a combustion chamber according to the invention.