In this paper, the relationship between the flow behavior and the pressure fluctuation was investigated because it was confirmed from the 1st and 2nd Report that the flow behavior was related to the pressure fluctuation.
In results, the flow became unstable in the transition region between the flow with a deposit bed and the one with a moving bed, and it was found that the pressure fluctuation became very large.
Furthermore, it was confirmed that the relationship between the velocity fluctuations of fluid and solid particles, and the flow behavior were the same as the one between the pressure fluctuation and the flow behavior. Therefore, it could be considered that the velocity fluctuations are related to the pressure fluctuation, and the simulation model of the pressure fluctuation containing the factor of velocity fluctuations of fluid and solid particles was proposed. The calculated values of the pressure fluctuations using this model were in good agreement with the experimental results.