# Numerical and Experimental Analysis of Pressure Pulsation Attenuator Based on Helmholtz Resonator
###### Abstract
In 2014, [PERSON] et al. [14] analyzed the damping performance of single-layer and one double-layer perforated liners in terms of the open area ratio and the number of perforated layers on the liner's damping. The results show that the double-layer perforated liners can improve the damping in the higher frequency range. In 2016, [PERSON] et al. [15] changed the top of the cavity of the Helmholtz resonator into a uniformly flexible end plate. By optimizing and changing the thickness of the end plate, the transfer loss was increased by 28% compared to the previous. [PERSON] et al. [16] carried out theoretical analysis and experiments on K-type and H-type attenuators. The results show that the pressure pulsation of the pump outlet is reduced by about two times, and the noise is reduced by about 4 dB on average. It has a good attenuation effect on pressure pulsation and noise. [PERSON] et al. [17] proposed a compound pressure pulsation attenuator with K-type and H-type in series, which effectively broadened the filtering range of the attenuator in high and low frequencies. Compared with the series H-type pulsation attenuator, the attenuation effect is better in the high-frequency range and the structure is more compact. [PERSON] et al. [18] investigated the acoustic damping performance of six different geometries of resonator neck orifices within the pipeline. As the Helmholtz number increased, the star-shaped orifice had lower power absorption compared to the other shapes. To reduce the pressure pulsation in the aircraft hydraulic system, [PERSON] et al. [19] proposed a multi-element buffer bottle by integrating a fluid filter with orifices, pipes, and T-shaped pipes. [PERSON] et al. [20] proposed a resonant based on elastic sheet elements, which transformed fluid resonance into structural resonance. It has good attenuation performance near the resonance frequency of the elastic sheet elements. [PERSON] et al. [21] proposed a string type hydraulic pulsation attenuator by combining elastic string with a resonant cavity and damping hole. Through simulation, the insertion loss is more than 15 dB in 450-1000 Hz. In 2020, [PERSON] et al. [22] designed a compound pressure pulsation attenuator consisting of several string-liquid resonators and an expansion chamber. Considering geometric optimization and computational efficiency, an adaptive particle swarm optimization algorithm is proposed [23]. Under the same input conditions, the attenuation effect is better than that of expansion chamber type, H-type, porous concentric type, and bionic cochlear type pulsation attenuators. [PERSON] et al. [24] analyzed a new circular elastic thin plate pressure pulsation attenuator, which solved the vibration problem in the linear-driven pump pipeline system. The experimental results show that the insertion loss is 26 dB at 6.67 Hz, and the elimination effect is the best. In 2021, [PERSON] [25] designed a new type of pressure pulsation attenuator by combining an expansion cavity and an H-type attenuator. Within 20-2000 Hz, the insertion loss reaches more than 50 dB, and the attenuation effect is good. [PERSON] et al. [26] studied and derived the model of a porous variable diameter Helmholtz pulsation attenuator (PVDHPA). By analyzing the attenuation characteristics of PVDHPA, the optimal diameters of damping holes and resonators are obtained. After PVDHPA is installed, the vibration signal in the frequency range of 200-400 Hz and 1000 Hz is eliminated significantly, and the vertical vibration impact is greatly reduced. [PERSON] [27] analyzes and compares the lumped parameter method and the distributed parameter method, which provides a theoretical basis for studying the fluid characteristics of hydraulic lines. Dr. [PERSON] [28] of the Technische Universitat Braunschweig and the University of Stuttgart [29] explored methods for pressure pulsation attenuation in hydraulic pipelines.