A combustion system, comprising: a liner disposed around a combustion region; a flow sleeve disposed around the liner, the liner and the flow sleeve cooperating to create an air passage having an airflow located between the liner and the flow sleeve; a flow-obstructing element disposed within the air passage, the flow-obstructing element generally obstructing the airflow in the air passage and creating wakes in the airflow; the flow obstructing element being one of a cross-fire tube, a flame detector, a spark plug, a liner stop, a boss, a pressure probe, and a sensor; and a venturi disposed downstream from the flow-obstructing element, the venturi defined by the flow sleeve and extending into the air passage, the venturi generally restricting and diffusing the airflow in the air passage to generally reduce wakes in the airflow, wherein the venturi includes a converging section defined by the wall of the flow sleeve that converges towards the liner, a diverging section defined by the wall of the flow sleeve that diverges downstream of the converging section, and a throat connecting the converging section with the diverging section and wherein the throat provides a reduction in a cross-sectional area of the air passage in the range of 20 to 70 percent and is located at a specified distance from the flow-obstructing element, wherein the specified distance is in the range of the dimension of the flow-obstructing element to about ten times the dimension of the flow-obstructing element, the dimension representing one of a width and a diameter of the flow-obstructing element; and wherein at least one air aperture is defined as a thru-hole within the flow-sleeve in the diverging section downstream of the throat. a liner disposed around a combustion region; a flow sleeve disposed around the liner, the liner and the flow sleeve cooperating to create an air passage having an airflow located between the liner and the flow sleeve; a flow-obstructing element disposed within the air passage, the flow-obstructing element generally obstructing the airflow in the air passage and creating wakes in the airflow; the flow obstructing element being one of a cross-fire tube, a flame detector, a spark plug, a liner stop, a boss, a pressure probe, and a sensor; and a venturi disposed downstream from the flow-obstructing element, the venturi defined by the flow sleeve and extending into the air passage, the venturi generally restricting and diffusing the airflow in the air passage to generally reduce wakes in the airflow, wherein the venturi includes a converging section defined by the wall of the flow sleeve that converges towards the liner, a diverging section defined by the wall of the flow sleeve that diverges downstream of the converging section, and a throat connecting the converging section with the diverging section and wherein the throat provides a reduction in a cross-sectional area of the air passage in the range of 20 to 70 percent and is located at a specified distance from the flow-obstructing element, wherein the specified distance is in the range of the dimension of the flow-obstructing element to about ten times the dimension of the flow-obstructing element, the dimension representing one of a width and a diameter of the flow-obstructing element; and wherein at least one air aperture is defined as a thru-hole within the flow-sleeve in the diverging section downstream of the throat.