使用商用軟體Ansys Fluent，對內置彈艙之矩形空穴(Cavity)模型進行數值模擬和聲場分析。使用SST-DES 混合模型，驗證在馬赫數於0.95之穿音速的條件下，空穴後壁面上之監測點K18與底部監測點K16之聲壓級SPL(Sound Pressure Level)分佈，以及空穴內部的流場分佈。之後再比較長深比4.5與長深比6兩者空穴之間後壁面上監測點之聲壓級的峰值。再來探討一矩形腔體物理模型L31其在開口處有鋸齒形狀與無鋸齒形狀對內部聲場所造成的差異性。此外並針對L31的物理模型彈艙內放置一枚飛彈，以此為機處探討攻角姿態於0、3以及5度情況下，彈艙模型內部的聲場變化，並用監測點來尋找可能產生的共振頻率與峰值。最後再探討飛彈的擺放方式來做分析，來探討不同擺放方式對後壁面頻率模態的影響。
本論文首先進行軟體驗證，空穴之聲場與美國空軍試驗中心風洞數據作比對，以此增加模擬數據可信度。本論文對L31進行物理模型建模，其大小以實際現代戰機尺寸進行設計，再運用上述驗證所得到的經驗設定，設定每組模擬，以此預測不同情況下L31內部與外部流場之物理量分布，以及重點分析的所感興趣之監測點的聲場頻譜圖數據。藉此分析在類似現代戰機的彈艙在艙門開啟的情況時，彈艙內部是否會因為聲壓級而對結構上可能對戰機產生的危害，以及提前預測出可能會與彈艙內部結構共振的頻率峰值。

The flow fields and sound pressure level of an internal weapon bay with rectangular cavity model of 4.5 were numerically simulated by using commercial software Ansys Fluent. The SST-DES hybrid turbulence model are applied. First, the Sound Pressure Level(SPL) distribution of the monitoring point K18 on the rear wall of Cavity and the bottom monitoring point K16 on the condition of Mach number 0.95 are simulated and compared with the known data. The peak sound pressure level of the monitoring point on the rear wall between the cavity between the L/D=4.5 and the L/D=6 are investigated. Also the difference between a rectangular cavity physical model L31 with a sawtooth shape at the opening and a non-sawtooth shape to the internal acoustic field. In addition, for the L31 physical model, a missile was placed in the bomb bay to investigate the sound field changes inside the bomb bay model at angles of attack of 0, 3, and 5 degrees. The possible resonance frequencies and peaks are analyzed. Finally, we discuss the placement of missiles for analysis to discuss the effect of different placement on the frequency mode of the rear wall.

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