This study investigates the breakup behavior of swirling liquid sheets discharging from gas-centered swirl coaxial atomizers, focusing on the role of the central gas jet in the breakup process. Cold flow experiments were conducted using custom fabricated gas-centered swirl coaxial atomizers with water and air as experimental fluids. Photographic techniques were employed to capture the flow behavior of liquid sheets at different flow conditions. Quantitative variations in the breakup length of the liquid sheet and spray width were obtained from image analysis. The central air jet significantly influences the breakup process. Low inertia liquid sheets are more vulnerable to the central air jet, developing shorter breakup lengths at smaller air jet Reynolds numbers (Re_g). High inertia liquid sheets ignore the central air jet at smaller Re_g values but develop shorter breakup lengths at higher Re_g values. The central air jet causes corrugations on the liquid sheet surface, promoting the formation of thick liquid ligaments. The level of surface corrugations increases with increasing Re_g. The entrainment process of air between the inner surface of the liquid sheet and the central air jet is the primary trigger for sheet breakup. The study shows that the breakup length decreases with increasing Re_g for low inertia liquid sheets, while the decrease is less severe for high inertia liquid sheets. The interaction between the central air jet and the liquid sheet leads to complex breakup patterns, including the formation of cellular structures and thick liquid ligaments. The results indicate that the central air jet plays a crucial role in the breakup process, with the breakup length being significantly influenced by the flow parameters We_l and Re_g. The study highlights the importance of understanding the interaction between the central air jet and the liquid sheet in gas-centered swirl coaxial atomizers for optimizing spray formation and combustion efficiency.This study investigates the breakup behavior of swirling liquid sheets discharging from gas-centered swirl coaxial atomizers, focusing on the role of the central gas jet in the breakup process. Cold flow experiments were conducted using custom fabricated gas-centered swirl coaxial atomizers with water and air as experimental fluids. Photographic techniques were employed to capture the flow behavior of liquid sheets at different flow conditions. Quantitative variations in the breakup length of the liquid sheet and spray width were obtained from image analysis. The central air jet significantly influences the breakup process. Low inertia liquid sheets are more vulnerable to the central air jet, developing shorter breakup lengths at smaller air jet Reynolds numbers (Re_g). High inertia liquid sheets ignore the central air jet at smaller Re_g values but develop shorter breakup lengths at higher Re_g values. The central air jet causes corrugations on the liquid sheet surface, promoting the formation of thick liquid ligaments. The level of surface corrugations increases with increasing Re_g. The entrainment process of air between the inner surface of the liquid sheet and the central air jet is the primary trigger for sheet breakup. The study shows that the breakup length decreases with increasing Re_g for low inertia liquid sheets, while the decrease is less severe for high inertia liquid sheets. The interaction between the central air jet and the liquid sheet leads to complex breakup patterns, including the formation of cellular structures and thick liquid ligaments. The results indicate that the central air jet plays a crucial role in the breakup process, with the breakup length being significantly influenced by the flow parameters We_l and Re_g. The study highlights the importance of understanding the interaction between the central air jet and the liquid sheet in gas-centered swirl coaxial atomizers for optimizing spray formation and combustion efficiency.