Bended HQ tubes have been introduced to minimize the size of these noise-reducing structures, and the tubes-noise-reducing capabilities and Lagrangian Coherant structures are analyzed. Firstly, the impact of tube length and width on noise reduction is elucidated using acoustic mode theories with numerical simulations. This indicates a necessary length requirement to effectively mitigate low-frequency noise. Based on this, the HQ tube parameters under the given model are determined. Then, using these parameters, three types of HQ tube structures in the form of bended tubes and original tubes were designed and a comparative analysis is conducted. The results show that when the length is fixed, the average noise transmission loss of original HQ tubes and bended HQ tubes differs by only 0.05 dB, whereas in a limited space, the average noise transmission loss of original tubes is 0.41 dB lower than that of bended tubes due to the reduction in tube length. Lastly, FTLE is employed to investigate the flow structures inside the tubes. Separation zones near the bends are discovered and their boundaries are delineated using FTLE. Consequently, the width of the HQ tubes is adjusted, restoring the noise reduction performance to the level of the original HQ tubes. In conclusion, the bended HQ tube presents an effective solution for noise reduction in limited spaces. The impact of bended tubes on flow structures can be regulated by changing the width of the HQ tubes, while ensuring its noise reduction effect.