Pressure Pulse Amplitude Research Articles

The impact of mechanical vibrations on pressure pulsation, considering the nonlinearity of the hydraulic valve

The article identifies some of the forces acting on hydraulic valves used in the civil and military vehicles. Particular attention was paid to the single-stage electrically controlled “on/off” hydraulic directional control valve. Special attention was focused on vibrations of hydraulic directional valve four ways, three positions (4/3) controlled by typical solenoids. Military vehicles can be a source of vibrations in low and high range of frequency. The spectrum of vibrations frequency is wide in this case. The value of the natural frequency of vibrations of the hydraulic directional control valve spool, whose body was affected by mechanical vibrations, was estimated. The paper shows that the natural vibrations of the directional control valve spool can coincide with the frequency of external vibrations acting on the valve from the ground. The mathematical description takes into account that when the spool is overdriven, the oscillating movement of the directional control valve spool is described by a model that takes into account the nonlinearity resulting from the fact that the spool is in the extreme position—it is a poor nonlinear mechanical system. The results of theoretical considerations were confronted with the results of experimental research. In addition, the presented modified model was used to assess the impact of the capacitance change on the value of the amplitude of pressure pulsations caused by the vibrations of the directional control valve spool.

Ocular Biomechanical Responses to Long-Duration Spaceflight.

Objective: To assess the impact of microgravity exposure on ocular rigidity (OR), intraocular pressure (IOP), and ocular pulse amplitude (OPA) following long-term space missions. OR was evaluated using optical coherence tomography (OCT) and deep learning-based choroid segmentation. IOP and OPA were measured with the PASCAL Dynamic Contour Tonometer (DCT). Results: The study included 26 eyes from 13 crew members who spent 157 to 186 days on the International Space Station. Post-mission results showed a 25% decrease in OPA (p < 0.005), an 11% decrease in IOP from 16.0 mmHg to 14.2 mmHg (p = 0.04), and a 33% reduction in OR (p = 0.04). No significant differences were observed between novice and experienced astronauts. Conclusions: These findings reveal previously unknown effects of microgravity on the eye's mechanical properties, contributing to a deeper understanding of Spaceflight-Associated Neuro-ocular Syndrome (SANS). Long-term space missions significantly alter ocular biomechanics and have the potential to become biomarkers of disease progression.

REDUCING THE VISCOSITY OF THE OIL MIXTURE BY A ROTARY PULSE APPARATUS IN UKHTA — YAROSLAVL OIL PIPELINE

Physical methods of exposure can be used to improve the rheological characteristics of viscous, resinous oils, the transportation of which through main pipelines requires additional operating costs. The authors of this article evaluated the effectiveness of the method for improving oil rheology due to multifactorial effects (shear loads, high–amplitude pressure pulses, developed turbulence) on a sample of a mixture of oils of the Ukhta - Yaroslavl oil pipeline in a rotary pulse apparatus (RIA). The specific power consumption for processing an oil sample was 2.84 kWh/m3. The initial rheological and physico-chemical parameters of the studied oil are described, according to which it is characterized as heavy, viscous, highly resinous oil. The analysis of the flow curves showed that, by the nature of the flow, the sample of a mixture of oils from the Ukhta — Yaroslavl main oil pipeline belongs to Newtonian liquids. The evaluation of the effectiveness of the multifactorial effect on the oil sample implemented in RIA was carried out using dimensionless coefficients showing the ratio of dynamic viscosity, the specific power required to maintain the flow of oil in a rotary viscometer before and after physical exposure to oil, as well as the ratio of the change in the energy of thixotropy of oil to the energy spent on the processing process. The samples were processed in an RIA-based installation, in which pressure pulsations, developed turbulence, and large shear loads are generated in the liquid flow. When comparing the viscosity values of untreated and treated mixed oil in a rotary pulse apparatus, the dynamic viscosity measured at 20 °C decreased by 8 %. The component composition of the oil after processing in RIA has practically not changed. Measuring the viscosity of oil before processing and immediately after processing in RIA shows a decrease in viscosity by more than two times, since the temperature of the oil flow increases after passing through RIA by more than 10 °C. The increase in oil temperature during processing is due to large shear stresses during its flow in slit channels and in the gap between the rotor and stator due to the large amplitude of pressure pulsations and flow velocity.The relaxation time of the rheological parameters of the treated oil was seven days.

Influence of staggered vane shunt plate on performance characteristics of reactor coolant pump

In order to explore the influence of the axial position of the shunt plate of staggered guide vane on reactor coolant pump(RCP), a mixed-flow RCP was taken as the model for numerical simulation. Based on the entropy production theory, the energy loss in the flow component under different flow conditions was analyzed, and the vortex core distribution in volute and the pressure pulsation at the hydrodynamic interface were studied. The results show the staggered guide vane reduces the head and efficiency slightly, the optimal scheme decreases by 0.9% and 0.6%. Placement of the shunt plate significantly influences entropy production within the guide vane and volute, especially when positioned near the front and back plates. When shunt plate is set centrally, the energy loss due to staggered guide vane is relatively smaller and closer to the original structure. The entropy production rate of guide vane inlet and shunt plate leading edge is higher, but with the increase of flow rate, the shunt plate leading edge is no longer the main location of energy dissipation. Middle placement of staggered guide vanes effectively reduces the outflow vortex band by Omega vortex analysis, and the amplitude of pressure pulsation at the interface decreases obviously.

Investigation on flow–acoustic resonance behaviors inside ducts with tandem cavities using a high-order spectral/hp element method

This study numerically investigates the flow–acoustic resonance behaviors inside ducts with tandem cavities, containing the flow-excited acoustic eigenmodes and elevated flow dynamics under self-sustained acoustic forcing. An advanced high-order spectral/hp element method integrated with implicit large-eddy simulations was utilized to solve the nonlinear compressible Navier–Stokes equations, which effectively identified the fully coupled self-sustained flow–acoustic resonance fields. The benchmark shallow cavity configuration with a length-to-depth (L/D) ratios of 2 was motivated by the experimental findings from Shaaban and Ziada [“Fully developed building unit cavity source for long multiple shallow cavity configurations,” Phys. Fluids 30, 086105 (2018)], in which the intensive flow–acoustic resonance was occurred at a Reynolds number of 1.3×105, and we further investigated three deeper cavity configurations with L/D of 1, 2/3, and 1/2 for numerical validation and further comparison. Subsequently, aeroacoustic characteristics were assessed by analyzing the wall pressure fluctuations, indicating broader resonance regions and augmented pressure pulsation amplitudes extending from main duct to local cavity volumes with larger cavity depths. As feedback, the intensified acoustic forcing can modulate the cavity flow dynamics into stronger fluctuation levels. Furthermore, the spectral proper orthogonal decomposition analysis was conducted on the pressure fields and velocity fields, respectively. The significant fluctuations in acoustic pressure were linked to transitional acoustic modes that were present as global modes in the main duct and local modes in tandem cavities. As for velocity analysis, coherent vortex structures were extracted along the cavity entrances. These vortex structures caused progressively amplified velocity fluctuations and classified the shear layers into two dynamic motions, i.e., a flapping motion in shallow cavities and a rolling-up motion in deep cavities.

Numerical Simulation and Model Test on Pressure Fluctuation and Structural Characteristics of Lightweight Axial Flow Pump

In order to explore the relationship between the hydraulic performance, pressure pulsation, and structural characteristics of lightweight axial flow pumps, this paper takes the axial flow pump as the research object and analyzes pressure pulsation and structural characteristics by changing the blade length and thickness to realize the lightweight design of the axial flow pump impeller. Compared with the initial scheme (Scheme 1), the mass of the impeller is reduced by 17.2% (Scheme 2) and 29.9% (Scheme 3), respectively. The lightweight axial flow pump (Scheme 2 and Scheme 3) has a lower pressure pulsation amplitude at the impeller outlet monitoring point under large flow conditions. After the lightweight design of the axial flow pump impeller, the blade becomes shorter, the mass becomes lighter, and the cavitation performance will become worse. The maximum equivalent stress of Scheme 2 and Scheme 3 is increased by 2.8% and 31.9%, respectively, compared to Scheme 1. The maximum deformation of Scheme 3 increased by 27% compared to Scheme 1. This research can provide guidance for the lightweight optimization design of the axial flow pump.

Dynamics of air temperature changes in the atmospheric boundary layer during the solar eclipse of March 29, 2006

The data of measurements of air temperature profiles in the atmospheric boundary layer (ABL) during the total solar eclipse on March 29, 2006 in Kislovodsk and at the Kislovodsk High-Mountain Scientific Station (KVNS) on the central shadow line are presented. The solar eclipse lasted from 14:08 to 16:27 local time, the total phase of the eclipse began at 15:15 and lasted 2:32. In development of the results obtained by us in our previous work, we compared the data on air temperature profiles at two points, Kislovodsk and KVNS. The influence of local conditions has been studied. It was shown that local conditions significantly affect both the amplitude of atmospheric pressure pulsations caused by a solar eclipse and their phase, as well as the nature of the change in the spectral density of air temperature with height in the range of periods corresponding to the duration of the solar eclipse. Based on the measurements of temperature profiles, the fluctuations of the atmospheric pressure difference at the level of the earth’s surface and at a certain height, up to which the temperature profiles were measured equal to 600 m, were reconstructed, caused by a solar eclipse, in coordinates: height – time has different trajectories in the case of Kislovodsk and KVNS. The difference in the trajectories of air temperature minima in Kislovodsk and at the KVNS determines both different delays in pressure minima relative to the beginning of the eclipse and time delays between surface pressure fluctuations at observation points as a whole. Also, a new method is proposed for determining the speed of ascending air currents using data on the altitude dependence of the time of reaching a minimum in temporal temperature variations caused by a solar eclipse. The changes in the spectral density of air are compared with height, the amplitude of the reconstructed atmospheric pressure pulsations in Kislovodsk and at the KVNS, and the speed of ascending air currents.

Analysis and study of transient characteristics of hydrogen circulation pump under different stopping modes

The internal flow field of the hydrogen circulation pump becomes more complex and flow process becomes more intense during the stopping process, strong vibration is generated to the pump and the working life of the pump is shortened. Therefore, the pressure pulsation at the inlet and outlet section, the radial force characteristics of the active rotor and the transient flow mechanism of the internal flow under different stopping modes are studied in this paper. The results show that the intake pressure and exhaust flow change greatly in exponential stopping mode, while the pressure pulsation amplitude decreases with the increase of stopping time in linear stopping mode. In addition, the radial force value of the active rotor in the exponential stopping mode is significantly smaller than that in the linear stopping mode, and the direction of the radial force Fx and Fy point to the negative direction of their respective axes.

Numerical study of rotating cavitation and pressure pulsations in a centrifugal pump impeller

To investigate the variations in the flow field of centrifugal pumps with different cavitation numbers, this study utilized the shear stress transport k–ω turbulence model and Zwart–Gerber–Belamri cavitation model to examine the correlation between stall vortices and cavitation flow. The findings indicate that cavitation consistently coincides with the formation of stall vortices, and the distribution of cavitation mirrors the pattern of stall vortex structure. Cavitation tends to develop and aggregate around stall vortices, obstructing a significant portion of inlet areas within the flow channel. As the cavitation number decreases, both the area and intensity of stall vortices increase. For cavitations margins σ = 0.41, 0.23, and 0.15, we observed propagation frequencies of stall vortices at fs = 2.7, 1.8, and 0.9 Hz respectively, as these frequencies decrease relative to impeller movement until reaching near-stationary states. The pressure pulsations in various flow channels exhibit distinct phase differences; smaller cavity numbers result in larger phase disparities along with a gradual reduction in pressure pulsation amplitude. These discoveries present effective strategies for controlling and reducing both cavity formation and pressure fluctuations within centrifugal pumps, thereby enhancing overall stability.

Experimental study on energy and hydraulic performance of the axial flow pumping device with bell-shaped inlet channel

Abstract Due to the unique inlet design of the axial flow pump device with a bell shaped inlet channel, there is currently insufficient quantitative research on its hydraulic characteristics. This study investigates the hydraulic behavior of a vertical axial flow pumping device equipped with a bell-shaped inlet channel, analyzing various blade angles. Energy, cavitation, runaway, and pressure pulsation characteristics were assessed through meticulous testing on a high-precision test bench. Experimental findings indicate that altering the blade angle of the vertical axial flow pumping device with a bell-shaped inlet channel can influence its overall efficiency to some extent. Moreover, as the pump’s blade angle increases incrementally, the device’s cavitation performance gradually diminishes. Pressure pulsation tests reveal a relatively minor amplitude of pressure pulsation at the impeller outlet, contrasting with a more pronounced amplitude observed at the guide vane outlet compared to the pump outlet. These research results provide valuable insights for the design and optimization of actual pumping stations.

Effect of baffles on internal flow characteristics of double-inhalation centrifugal pumps under low flow conditions

In order to investigate the impact of baffles in the inhalation chamber on the external characteristics and operational stability of a double inhalation centrifugal pump under low flow conditions, the flow field simulation software ANSYS CFX and the shear stress transport formulation were employed to numerically simulate the internal flow field of a double inhalation centrifugal pump with and without baffles. Two models were subjected to performance curve simulation and prediction, with the internal flow field, pressure pulsation, and impeller force of the two models being compared and analyzed under three small flow conditions of 0.6Qd (rated flow), 0.5Qd, and 0.4Qd. The velocity and vortex distribution inside the semi-spiral inhalation chamber, as well as their impact on the flow state in front of and inside the impeller, were analyzed. Research has demonstrated that the addition of baffles can enhance the pump head and efficiency in flow conditions of 0.5Qd–0.8Qd. However, there is a tendency for obstruction of flow in conditions below 0.5Qd. Baffles can reduce the amplitude of pressure pulsation within the impeller and the radial force exerted by the impeller as a whole. Consequently, the incorporation of baffles within the inhalation chamber during flow conditions of 0.5Qd–0.8Qd can enhance the operational efficacy of the pump. Nevertheless, within the flow range of &amp;lt;0.5Qd, the pump's performance will decline. This study serves as a foundation for the design of double inhalation centrifugal pumps with semi-spiral inhalation chambers.

Effect of sediment erosion on pressure pulsations in a large Pelton turbine

AbstractPelton turbines functioning in sandy river environments often encounter difficulties due to the swift movement of sediment particles, leading to erosion and damage to overflow components. These challenges can result in operational instability, particularly noticeable in large turbines. Pressure pulsation is crucial for turbine stability, and alterations in overflow component profiles caused by sediment erosion can worsen pressure pulsations. This study utilizes numerical simulations to analyze turbine pressure pulsations based on surface profile changes of runner buckets after 2 and 4 years of sediment erosion in a single 500 MW large‐scale Pelton turbine. Our findings reveal that erosion leads to a gradual decrease in pressure pulsation along the bucket's splitting edge from the notch to the root. After 4 years of erosion and wear, the relative pressure pulsation amplitude in the root region increased by more than 530%. Additionally, changes occur in the thickness of the water film in the erosion area on the working surface, disrupting the flow pattern and generating more vortices. This occurrence intensifies the relative pressure pulsation amplitude and reduces bucket stability. The study findings highlight the significant impact of sediment erosion on Pelton turbine pressure pulsation, posing a considerable risk to the unit's operational stability and safety.

The Alteration of Intraocular Pressure and Ocular Pulse Amplitude by Retrobulbar Anaesthesia-A Search for Risk Factors for Serious Complications Due to Retrobulbar Anaesthesia.

Our goal was to assess the impact of retrobulbar anaesthesia on ocular pressure and perfusion development and to find out if there were systemic or biometric parameters of patients affecting them in order to understand the effect of retrobulbar anaesthesia better. Methods: Changes in intraocular pressure (IOP) and ocular pulse amplitude (OPA) using a dynamic contour tonometer (DCT) were noted before and after retrobulbar anaesthesia (RBA) in combination with five minutes of oculopression at 40 mmHg in 134 patients. Only results with a quality Q 1-3 were considered for further statistical analysis. Systemic and ophthalmic parameters were noted and their impact was tested using linear regression. Results: IOP decreased from 18.9 ± 7.2 mmHg to 15.4 ± 6.3 mmHg (n = 71, p = 0.001) after first RBA. The dosage of midazolam administered during premedication was found to increase IOP significantly after first RBA (B = 3.75; R2 = 0.38). Ocular pulse amplitude decreased significantly from 3.8 ± 1.7 mmHg to 3.0 ± 1.9 mmHg after first RBA (n = 72, p < 0.001). This change was found to be dependent on the presence of diabetes mellitus (n = 68, p = 0.048). Conclusions: IOP and OPA decrease after RBA and oculopression. Caution is needed with midazolam premedication due to potential IOP increase. Patients with diabetes and pre-existing retinal or optic nerve damage should consider alternative anaesthesia methods, such as eye drops or general anaesthesia, due to the observed decrease in OPA after RBA and oculopression.

Effect of liquid level monitor gas injection point size on information source amplitude-frequency characteristics

In order to analyse the effect of the injection point size of the CBM (Coalbed Methane) well level monitor on the amplitude and frequency of pressure pulsations in the wellhead manifold, numerical simulations and experiments were carried out to investigate the effect of different injection point sizes on the amplitude and frequency of pressure pulsations downstream of the sudden expansion structure. Using compressed air as the fluid and the size of the injection point as the variable, the amplitude and frequency of pressure pulsations at different locations downstream of the sudden expansion structure were tested. The results show that the pressure pulsation amplitude is affected by the size of the injection point, and the larger the injection point is, the larger the pressure pulsation amplitude is; the size of the injection point has less influence on the pressure pulsation frequency downstream of the protruding and expanding structure, and the pressure pulsation frequency at 0.5 m and 1 m downstream of the protruding and expanding structure is in the vicinity of 76 Hz. Therefore, the echo signal processing should be filtered around this frequency to obtain accurate liquid level echo signals, so as to improve the accuracy of liquid level monitoring and realise the efficient development of coalbed methane wells.

Effect of conversion time on the stability of mixed-flow pump in rotating speed conversion

The rotating speed conversion strategy has a significant impact on the stability of the variable speed operation of the mixed flow pump. Taking a mixed-flow pump as the research object, this paper collects the shaft vibration, pressure pulsation, and external characteristic parameters under different conversion times based on the synchronous acquisition system, and analyzes the influence of conversion time on these parameters. Finally, based on the improved TOPSIS evaluation method, the influence of different conversion time on the stability of the mixed-flow pump is evaluated. The results indicate that the conversion time is positively correlated with the amplitude of shaft vibration and pressure pulsation in the pump during the transition of rotating speed reduction. The local rubbing of the shaft can induce the vibration component corresponding to the high harmonics frequencies such as 2 f n, 3 f n, and 4 f n. The high correlation frequency band of the impeller outlet pressure pulsation and shaft vibration is located between 64 Hz and 120 Hz. And this frequency band is not affected by the conversion time. According to the TOPSIS evaluation results, in the transition process of speed reduction, the longer the rotating speed conversion time, the worse the stability of the mixed-flow pump during the conversion process.

Study on cavitation and pulsation characteristics of a novel rotor-radial groove hydrodynamic cavitation reactor

Abstract Hydrodynamic cavitation is widely used in many fields such as water treatment, impact rock breaking, and food preparation. The performance of hydrodynamic cavitation is closely related to its internal flow field. In the present study, cavitation flow field was analyzed by computational fluid dynamics in the reactor. The cavitation performance of the rotor is evaluated under different operating conditions. The time frequency distribution of pressure pulsation is studied. The pressure increases at the connection point between the local low-pressure area and the mainstream low-pressure area. Cavitation bubbles collapsed at the tail end of the cavity to form a local void area. The blade frequency amplitude of pressure pulsation shows the significant periodic change. The blade frequency amplitude decreases along the flow direction. The effect of the fluid outlet led to the increase in the second-order harmonic frequency amplitude. The research results could provide theoretical support for the research of cavitation mechanism of cavitation equipment.

Intracranial pulse pressure amplitude as an indicator of intracranial compliance: observations in symptomatic children with Chiari malformation type I.

Reduced intracranial compliance (ICC) may be an important factor in the pathophysiology of Chiari malformation type I (CM-I). However, direct measurement of ICC is controversial because of its invasiveness, particularly in children. Instead, ICC may be estimated from continuous measurements of intracranial pressure (ICP), where the metric mean wave amplitude (MWA) has been found to be more useful as a surrogate marker of ICC than mean ICP. This observational study investigated the distribution of MWA and mean ICP in symptomatic children with CM-I, as well as their association with clinical and radiological findings. From a consecutive series of children treated for CM-I at a single institution between 2006 and 2023, the authors analyzed ICP scores in those who underwent an overnight preoperative ICP recording in which MWA was calculated. Clinical and radiological data were retrieved from the patient records. Thirty-seven children (mean age 12.4 ± 3.6 years) with symptomatic CM-I were identified. From the overnight ICP measurements, the average MWA was 5.2 ± 1.3 mm Hg: 56% of children had an abnormal MWA (> 5 mm Hg) and 33% had a borderline MWA (4-5 mm Hg). In contrast, the average mean ICP was 9.7 ± 4.1 mm Hg: 8% of children had an abnormal mean ICP (> 15 mm Hg) and 41% had a borderline mean ICP (10-15 mm Hg). Thus, more children were found to have an abnormal MWA than an abnormal mean ICP (p < 0.001). MWA was significantly higher in the subgroup of children with medullary compression in the foramen magnum, as seen on MRI, than in those without (5.6 ± 1.0 mm Hg vs 4.7 ± 1.4 mm Hg, p = 0.03), whereas a similar difference was not observed for mean ICP (9.9 ± 4.6 mm Hg vs 9.7 ± 3.7 mm Hg, p = 0.889). In this cohort of symptomatic children with CM-I, MWA was more frequently abnormal than mean ICP, with a clinically significant discrepancy in half of the patients. Moreover, MWA was significantly higher in patients with medullary compression. Based on these findings, the authors' interpretation is that in children with CM-I, the ICC may be reduced, as indicated by increased MWA, even though the mean ICP is within normal thresholds.

Pressure Pulsation Analysis of 2D NACA66 Airfoil Based on Pulsation Tracking Network

Abstract The NACA66 airfoil is used extensively in the design of turbine runners and as a core component, the airfoil plays a vital role in the operation of the turbine. In order to investigate the details of the effect of the NACA66 airfoil on pressure pulsation, this paper investigates and analyses the NACA66 airfoil with a work angle of 14°. This study combines computational fluid dynamics (CFD) with pulsation tracking network (PTN) technology to numerically simulate the NACA66 airfoil. The simulation results show that the dominant pressure pulsation frequencies in the computational domain are mainly 100hz, 3500hz, and 6900hz, and the pressure pulsation amplitude varies for different dominant frequencies. When the dominant frequency is 100hz and 3500hz, the pressure pulsation amplitude continues to decrease from the inlet to the outlet of the calculation domain, but a small increase in pressure pulsation amplitude occurs at the trailing edge of the airfoil. When the dominant frequency is 6900hz, the pressure pulsation amplitude decreases from the inlet to the outlet of the calculation domain and increases sharply below the airfoil, which is greater than the pulsation amplitude in the surrounding area. This paper reveals the dominant frequency of the NACA66 airfoil disturbance based on PTN technology and the variation of the pressure pulsation amplitude at different dominant frequencies. The content of this study can help to explore more deeply the pressure pulsation problem generated by airfoil winding and provide ideas for solving the pressure pulsation engineering problem.

Vibration of Variable Speed Pump-Turbine in Turbine Operating Range: Simulation by CFD+FEM

Abstract Variable speed pumped-storage unit can operate efficiently and stably in wide range of power and head through the coordinated control of the rotational speed and guide vanes. The regulation in rotational speed brings about frequency and amplitude changes of pressure pulsations, which further influence the avoidance margin of vibration and the dynamic response of the runner. The vibration characteristics of the variable-speed pump-turbine need to be studied when it runs in the wider operating region. Selecting an actual pumped-storage unit as the subject and using the CFD+FEM coupled simulation method as a tool, we conducted three-dimensional pump-turbine vibration simulations and analyse the flow patterns, pressure pulsations, and runner vibration characteristics of several typical operating points in turbine mode. The study focused on the variation laws of pressure pulsations and dynamic stresses when rotational speed is regulated. Comparison with the results for the constant speed unit under the corresponding working conditions was conducted. It is shown that the variable speed operation can effectively avoid the severe vibration conditions that the constant speed unit encounters; the amplitudes of pressure pulsations and dynamic stresses of the runner are small at low rotational speed; in the condition of high speed, low head, and small load, the vibration is the most obvious. This study can provide a reference for the design and operation of variable speed pump-turbine.

Analysis of low frequency pulsation and profile modification of turbine control valve

During the operation of a nuclear power steam turbine's main control valve, the valve frequently operates at a small opening and pressure ratio, causing intense alternating loads and oscillation. To address this, a transient numerical simulation studied low-frequency pulsation and optimized steam. Results showed high amplitude and wide frequency range flow pulsations on the spool and tube wall due to repeated flow field separation. By improving the valve core profile, control over the valve throat jet state reduced pressure pulsation amplitudes significantly, as well as mitigating flow-induced vibration in the valve core cavity and pipeline.