Intense tonal sound often radiates from flows around a trailing edge with an upstream kink shape such as found in automotive body. To clarify the conditions for the acoustic radiation, sound pressure and flow fields are measured in wind tunnel experiments. As a result, intense acoustic radiation occurs when both flow separation around a kink shape and reattachment near the trailing edge occur. Moreover, to clarify fluid-acoustic interactions, which are related with the radiation, the method of coherent output power (COP) was utilized based on coherence analysis. This method identified the positions for generation of vortices and acoustic source.