The compressed air energy storage gas turbine (CAES-G/T), an innovative method of meeting peak demand requirements of electric utilities is now on the installation in Japan, where surplus power is used to compress air and store it in a high-pressure underground circular horizontal cavern. Then it serves as a supply to help drive a gas turbine during periods when extra generating capacity is needed. The ultimate objective of the present study is to develop a methodology to analyze the unsteady state response of outlet air temperatures to a variation of the temperature inside and of the cavern. In the present work, an analytical model based on the two-dimensional laminar flow on the cross-section of the circular cylinder was developed to quantify the effect of the transient process occurring in the cavern and wall during injection, storage and release of the compressed air in the experimental circular cavern. It was found that the stratified temperature distribution was maintained in the cavern during compression and expansion periods. The wall temperature varied together with the variation of the air temperature with time, leading to the heat storage and/or release in the wall.