<p>To develop a detonation combustion chamber intake channel with a short axial length, minimal resistance to the incoming flow, and effective suppression of back-propagating pressure waves, this study investigated a novel intake structure consisting of a U-shaped channel. The study investigated the effects of obstacles with different geometric parameters installed at different positions within the U-channel on the attenuation of pressure waves. To standardize the channel structure, the concept of a gas retention volume ratio is introduced and systematically studied as a key parameter. The findings reveal that the flow area ratio of the channel is the most significant factor influencing the attenuation of pressure waves, while variations in the gas retention volume ratio also affect the wave propagation process. Furthermore, the study reveals that installing obstacle structures in the downstream leg of the U-channel results in bidirectional anisotropy, characterized by different total pressure recovery coefficients for forward and reverse flows.</p>