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 . <EOS>