3D Unsteady Flow Research Articles

Water Level Forecasting Combining Machine Learning and Ensemble Kalman Filtering in the Danshui River System, Taiwan

Taiwan faces intense rainfall during typhoon seasons, leading to rapid increases in water level in rivers. Accurate flood forecasting in rivers is essential for protecting lives and property. The objective of this study is to develop a river flood forecasting model combining multiple additive regression trees (MART) and ensemble Kalman filtering (EnKF). MART, a machine learning technique, predicts water levels for internal boundary conditions, correcting a one-dimensional (1D) unsteady flow model. EnKF further refines these predictions, enabling precise real-time forecasts of water levels in the Danshui River system for up to three hours lead time. The model was calibrated and validated using observed data from four historical typhoons to evaluate its accuracy. For the present time at three water level stations in the Danshui River system, the root mean square error (RMSE) ranged from 0.088 to 0.343 m, while the coefficient of determination (R2) ranged from 0.954 to 0.999. The validated model (module 1) was divided into two additional modules: module 2, which combined the ensemble unsteady flow model with inner boundary correction and MART, and module 3, which featured an ensemble 1D unsteady flow model without inner boundary correction. These modules were employed to forecast water levels at three stations from the present time to 3 h lead time during Typhoon Muifa in 2022. The study revealed that the Tu-Ti-Kung-Pi station was less affected by inner boundaries due to significant tidal influences. Consequently, excluding the upstream and downstream boundaries, Tu-Ti-Kung-Pi station showed a superior RMSE trend from present time to 3 h lead time across all three modules. Conversely, the Taipei Bridge and Bailing Bridge stations began using inner boundary forecast values for correction from 1 h to 3 h lead times. This increased the uncertainty of the inner boundary, resulting in higher RMSE values for these locations in modules 1 and 2 compared to module 3.

On the Performance of a Data-Driven Backward Compatible Physics-Informed Neural Network for Prediction of Flow Past a Cylinder

Abstract This paper discusses a physics-informed surrogate model aimed at reconstructing the flow field from sparse datasets under a limited computational budget. A benchmark problem of 2D unsteady laminar flow past a cylinder is chosen to evaluate the performance of the surrogate model. Earlier studies were focused on forward problems with well-defined data. The present study attempts to develop models capable of reconstructing the flow-field data from sparse datasets mirroring real-world scenarios. We demonstrated the performance of data-driven models in reconstructing the flow field and compared the effectiveness of various training methodologies. The proposed surrogate model successfully reconstructed the flow field while also extracting pressure as a latent variable. The proposed surrogate model significantly outperformed data-driven models in accuracy, even under a limited computational budget. Furthermore, transfer learning of parameters of a pretrained model for different Reynolds numbers has reduced training time.

Scenario-based HEC-RAS 2D unsteady flow analysis of Shisper Lake for GLOF risk assessment

Scenario-based HEC-RAS 2D unsteady flow analysis of Shisper Lake for GLOF risk assessment

Including dynamic capacity impact in an improved model for optimal flood control operation in river-type reservoirs

Flood control operations in river-type reservoirs are significantly affected by both the dynamic reservoir capacity and flood propagation within the reservoir area. However, the traditional reservoir flood control optimal operation (RFCOO) model is usually based on the static capacity method, which may bring large errors in scheduling calculations for river-type reservoirs. To address this issue, an improved model, the reservoir dynamic capacity flood control optimal operation (RDCFCOO) model, that includes the influence of the dynamic reservoir capacity and flood propagation, was developed to improve the accuracy of flood regulation calculations in river-type reservoirs. This improved model includes a 1D unsteady flow simulation and a rederived objective function based on the maximum peak clipping criterion, and expresses the state transformation equations using the de Saint-Venant equations. Furthermore, a multi-core parallel DP (PDP) algorithm that incorporates reduction of state dimensionality (RSD) was developed to effectively derive optimal operation schemes. The improved model and algorithm developed herein were validated through an application to the Xiangjiaba Reservoir, China. The results show that: (1) By adding the item (qiw) to the objective function and substituting the de Saint-Venant equations for the water balance equation, the RDCFCOO model developed in this paper can account for the impact of dynamic capacity and flood propagation. As a result, it exhibits a more accurate and detailed flood control process that was closer to the actual conditions of river-type reservoirs compared to the RFCOO model; (2) By removing the invalid discrete state points from the search space and fully utilizing multi-core processors, the proposed PDP with RSD can significantly improve the computational efficiency of the DP in solving RDCFCOO problems. The improved model and algorithm can effectively improve the calculation accuracy of flood control optimal scheduling in river-type reservoirs and provide more information for decision-makers.

FLOOD INUNDATION MAPPING OF GODAVARI RIVER BY USING 2D HEC-RAS MODEL

Due to increasing urbanization, there are various drastic changes taking place in environment these changes are hazardous for human being as well as animal and environment. Effect of environmental degradation can create environmental issues such as flood, drought etc. Out of this flood is the most common and disastrous hazard in the world. Present study utilizes 2D Unsteady flow modelling for flood inundation mapping in the lower Godavari basin for a reach length of 70 km from Sambaigudem in Telanagana district of Ramanujavaram to Damaracherla in Andhra Pradesh district of Nalgonda. For analysis of this 2D flow modelling and inundation mapping 30m resolution DEM is used. From ancient time majority of cities are developed near or on the banks of the river and these cities were affected due to flood during rainy season or due to the high intensity rainfall. As India is among the most vulnerable to flooding because of its geographical features. Therefore, this study is performed to analyze the flood plain and the extent of the affected areas present on or near the bank of Godavari River and provide mitigation measures for it.

Kajian Tanggul Pengendali Banjir di Kali Pengkol - Kota Semarang

The Pengkol River, situated in Meteseh, Tembalang sub-district of Semarang City, underwent three significant flood occurrences from January to February 2023. An approach involving a structural flood control system, specifically a levee, was suggested as a solution to this issue. The objective of this research is to establish the arrangement and highest elevation of the levee flood control and evaluate its effectiveness in mitigating floods. To determine flood hydrographs, a hydrological analysis was carried out using the Rainfall-Runoff simulation with the SCS Curve Number method. Additionally, a hydraulic analysis was performed using Unsteady Flow simulation with HECRAS 1D/2D hydrodynamic models to define the river body, water profile, inundation, and levee design. The hydrologic analysis indicates that the flood discharge for the 50, 100, and 200-year return periods are 209.5 m³/sec, 225.1 m³/sec, and 240.6 m³/sec, respectively. Based on the hydraulic analysis, the maximum water levels resulting from these return periods' flood discharges are +35.62 m (Q50 years), +35.77 m (Q100 years), and +36.43 m (Q200 years). The Q200 years of return period was chosen for 2D modeling because it resembles documented flood occurrences. Using the HECRAS 2D Unsteady Flow model, it was found that before the levee implementation, the flooded area within the residential zone spanned 9462 m², with a peak water level of +37.3 m. With the levee application, using an existing layout with a total length of 230 m and a top levee level of +37.5 m, flooding was effectively prevented, reducing the maximum water surface elevation to +37.17 m. This demonstrates the levee's effectiveness in preventing floods.Keywords: levee, flood, HECRAS 1D 2D model, inundation. Unsteady flow.

Flow front mobility of rock avalanches as a function of flow volume, grain size, channel width, basal friction and flow scale

The ability to predict the mobility of rock avalanches is necessary when designing strategies to mitigate the risks they pose. A popular mobility indicator of the flow front is the Heim’s apparent friction coefficient μH\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mu }_{H}$$\\end{document}. In the field, μH\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mu }_{H}$$\\end{document} shows a decrease in value as flow volume V increases. But this correlation has been a mystery as to whether it is due to a causal relationship between V and mobility since: (1) field data of μH\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mu }_{H}$$\\end{document} do not collapse onto a single curve because typically widely scattered and (2) laboratory experiments have shown an opposite volume effect on the center of mass mobility of miniature flows. My numerical simulations confirm for the first time the existence of a functional relationship of scaling parameters where μH\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mu }_{H}$$\\end{document} decreases as V increases in unsteady and nonuniform 3D flows. Data scatter is caused by μH\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mu }_{H}$$\\end{document} that is affected by numerous other variables besides V. The interplay of these variables produces different granular regimes with opposite volume effects. In particular, μH\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mu }_{H}$$\\end{document} decreases as V increases in the regime characterized by a relatively rough subsurface. The relationship holds for large-scale flows that, like rock avalanches, consist of a very large number of fine clasts traveling in wide channels. In these dense flows, flow front mobility increases as flow volume increases, as channel width increases, as grain size decreases, as basal friction decreases and as flow scale increases. Larger-scale flows are more mobile because they have larger Froude number values.

Numerical Modelling of the 3D Unsteady Flow of an Inlet Particle Separator for Turboshaft Engines

Helicopter and turboprop engines are susceptible to the ingestion of debris and other foreign objects, especially during take-off, landing, and hover. To avoid deleterious effects, filters such as Inlet Particle Separators (IPS) can be installed. However, the performance and limitations of these systems have to be investigated before the actual equipment can be installed in the aircraft powerplant. In this paper, we propose different numerical methods with increasing resolution in order to provide an aerodynamic characterization of the IPS, i.e., from a simple semi-empirical model to 3D large eddy simulation. We validate these numerical tools that could aid IPS design using experimental data in terms of global parameters such as separation efficiency and pressure losses. For each of those tools, we underline weaknesses and potential benefits in industry practices. Unsteady flow analysis reveals that detached eddy simulation is the trade-off choice that allows designers to most effectively plan experimental campaigns and mitigate risks.

Dynamics and dispersion of inertial particles in circular cylinder wake flows: A two-way coupled Eulerian–Lagrangian approach

In this paper, the motion of inertial particles in three-dimensional (3D) unsteady cylindrical wake flow is investigated by a two-way coupled Eulerian–Lagrangian approach. At different flow Reynolds numbers (Re), the corresponding striking dynamic property and dispersion mechanism of four particle classes have been studied, with inertia parameterized by means of Stokes number (Sk). It is found that inertial particles with lower Stokes number are expelled from vortex cores, and coherent voids encompass the local Kármán vortex cells. As Stokes number increases, a low velocity particle channel could be formed, which almost coincides with the results in the literature. Moreover, with the increase of Reynolds number, numerous irregular coherent voids are observed in the cylinder wake, and the high-speed particles follow the fluid flow closely when they are contained in the vortices. Although the centrifugal force of Kármán vortex cells significantly affects the dynamics of inertial particles, the fluid flow modulation is believed to be responsible for the distinctive particle dispersion patterns in the vortex streets. For particles with medium inertia, the two-way coupled modulation weakens the centrifugal effect of vortex structures on the particles. This trend declines with the increase of Reynolds number, and vanishes with light particles, while both two-way coupled modulation and the centrifugal effect of vortex structures are almost equally effective with heavy particles. The investigations contribute to a better understanding of the particle-laden flows in practical applications, which will benefit the optimized design of certain machinery and equipment for the industry.

The effect of variable rotary motion of a flapping wing rotor on its aerodynamic performance based on an improved unsteady vortex ring method

In the previous aerodynamic analysis using a potential flow-based unsteady aerodynamic model for the flapping wing rotor (FWR), the average rotary velocity and flapping frequency together with the flapping and twist angles are usually taken as the FWR kinematics of motion. In the present study, an unsteady vortex ring method (UVRM) is developed to take the rotary velocity variation of the FWR during the flapping motion into account based on 3D unsteady potential flow theory. The UVRM is validated by comparing with the published results of a flapping wing and an FWR model. An FWR test model and the corresponding experimental platforms including a wing motion tracking system and a force measurement system are built to measure the FWR motion and associated forces. Three FWR test cases of different input voltages and kinematics of flapping motion are considered to measure the aerodynamic forces and compare with the UVRM results. The results show that the differences between the measured and pre-set flapping angles (-50°∼ 20°) for the FWR are negligible for all the cases, but the differences in the variation amplitudes of the measured twist angle and the corresponding pre-set rigid twist angles can be as much as about 15°. Also, the FWR rotary velocity varies dramatically during a flapping cycle. For one of the cases with the -10°∼30° pre-set twist angle and 4 V input voltage, the difference between the maximum and minimum rotary speed is about 1451°/s, which makes a significant effect on the FWR aerodynamic performance. The results also show that the calculated lift forces using the UVRM and the measured real-time rotary speeds during a flapping motion are very close to the experimental results. While the calculated results by taking the FWR's average rotary speeds show apparent differences (up to about 25%) from the measured lift forces in most of the cases. Overall, the UVRM provides an efficient method for the FWR aerodynamic analysis with higher accuracy by taking the effect of variable rotary motion and twist angle of the FWR during a flapping cycle into account.

Numerical analysis for 3D time-dependent Sutterby nanofluid flow capturing features of variable thermal conductivity and heat sink-source aspects

Presently, due to its extraordinary mechanical, thermal, electrical and biomedical facets nanofluids deliver several prospects to exaggerate the propensity of isothermal systems by augmenting the conductivity features of the host fluids. In various areas of the energy partition, nanoparticles show a remarkable measure in energy storage, energy variation, and energy convertible, i.e. thermoelectric plans, petroleum cells, supercapacitors, stellar cells, rechargeable batteries, light-radiating diode and carbon-based light-radiating diode, smart coatings. In this current conversation, we anticipated an unsteady 3D flow of the Sutterby nanofluid consequence of a bidirectional extended surface. To envision the thermophoresis and Brownian motion properties in Sutterby’s nanofluid, the Buongiorno association is utilized in an additional refined technique. Variable thermal conductivity with heat source/sink property occurred deliberated considering heat transmission techniques. The appropriate transformation is applied for transposing the PDEs into nonlinear ODEs. For numerical results, the bvp4c programmed is prerequisite for elucidating the subsequent Ordinary differential equations. The distinct performance of the Sutterby nanofluid temperature and the concentration field are designated and discussed in the physical parameter’s aspect. It is clear that the temperature of the Sutterby fluid decreases with respect to the ratio of stretching rates parameter and similar developments are observed for the thermophoresis and Brownian motion parameters. Furthermore, the concentration profile declines for sophisticated estimates of the Lewis number and thermophoresis parameters.

Regularity criterion for 3D generalized Newtonian fluids in BMO

In this paper, we prove that a weak solution of the Cauchy problem for 3D unsteady flows of a generalized Newtonian fluid becomes a strong solution for 53<p<115 provided that the velocity field belongs to the critical space L2p−1(0,T;BMO(R3)). The main key is to apply variants of Gagliardo–Nirenberg's inequality including a BMO-norm. In particular, when 2<p<115, we derive and use a nonlinear variant of Gagliardo–Nirenberg's inequality including ‖u‖BMO and ‖|Du|p−22∇2u‖2.

3D MHD Radiation Flow of Unsteady Casson Fluid with Viscous Dissipation Effect

A numerical evaluation of the crucial physical properties of a 3D unsteady MHD flow along a stretching sheet for a Casson fluid in the presence of radiation and viscous dissipation has been carried out. Meanwhile, by applying similarity transformations, the nonlinear partial differential equations (PDEs) are transformed into a system of ordinary differential equations (ODEs). Furthermore, in the numerical solution of nonlinear ODEs, the shooting method along with Adams Moulton method of order four has been used. The obtained numerical results are computed with the help of FORTRAN. The tables and graphs describe the numerical results for different physical parameters which affect the velocity and temperature profiles.

Code Verification for the SENSEI CFD Code

Abstract This work performs systematic studies for code verification for turbulence modeling in our research CFD code SENSEI. Turbulence modeling verification cases including cross term sinusoidal manufactured solutions and a few exact solutions are used to justify the proper Spalart–Allmaras and Menter’s SST turbulence modeling implementation of the SENSEI CFD code. The observed order of accuracy matches fairly well with the formal order for both the 2D/3D steady-state and 2D unsteady flows when using the cross term sinusoidal manufactured solutions. This work concludes that it is important to keep the spatial discretization error in a similar order of magnitude as the temporal error in order to avoid erroneous analysis when performing combined spatial and temporal order analysis. Since explicit time marching scheme typically requires smaller time-step size compared to implicit time marching schemes due to stability constraints, multiple implicit schemes such as the singly diagonally implicit Runge–Kutta multistage scheme and three point backward scheme are used in our work to mitigate the stability constraints.

A hybrid projection/data-driven reduced order model for the Navier-Stokes equations with nonlinear filtering stabilization

We develop a Reduced Order Model (ROM) for the Navier-Stokes equations with nonlinear filtering stabilization. Our approach, that can be interpreted as a Large Eddy Simulation model, combines a three-step algorithm called Evolve-Filter-Relax (EFR) with a computationally efficient finite volume method. The main novelty of our ROM lies in the use within the EFR algorithm of a nonlinear, deconvolution-based indicator function that identifies the regions of the domain where the flow needs regularization. The ROM we propose is a hybrid projection/data-driven strategy: a classical Proper Orthogonal Decomposition Galerkin projection approach for the reconstruction of the velocity and the pressure fields and a data-driven reduction method to approximate the indicator function used by the nonlinear differential filter. This data-driven technique is based on interpolation with Radial Basis Functions. We test the performance of our ROM approach on two benchmark problems: 2D and 3D unsteady flow past a cylinder at Reynolds number 0≤Re≤100. The accuracy of the ROM is assessed against results obtained with the full order model for velocity, pressure, indicator function and time evolution of the aerodynamics coefficients.

Various Wavy Leading-Edge Protuberance on Oscillating Hydrofoil Power Performance

This paper is presented to compare various wavy leading-edge protuberances on oscillating hydrofoil performance and power efficiency. The unsteady turbulent 3D flow simulations were carried out by using the StarCCM+ software. The 3D hydrofoil with a straight at the leading-edge is a NACA0015 section with a chord of 0.24 m and an aspect ratio of 7. Four new types of hydrofoils are proposed with wavy leading-edge protuberance. The RANS equations with the realizable k–ε turbulence model are used to predict the turbulent flow around the hydrofoil under different conditions. In order to validate, a comparison of the numerical results of the forces coefficients and power efficiency of non-protuberance oscillating hydrofoil are shown in good agreement with experimental data. Then, four new profiles on the leading-edge of the hydrofoils are simulated and many results of the pressure distribution, vorticity contour, streamline velocity, and power coefficient for five hydrofoil types are presented and discussed. It is concluded that the hydrofoil of Type-M can achieve constantly higher efficiency of over 46% by employing appropriate heave and pitch amplitudes.

A data-based reduced-order model for dynamic simulation and control of district-heating networks

This study concerns the development of a data-based compact model for the prediction of the fluid temperature evolution in district heating (DH) pipeline networks. This so-called “reduced-order model” (ROM) is obtained from reduction of the conservation law for energy for each pipe segment to a semi-analytical input–output relation between the pipe outlet temperature and the pipe inlet and ground temperatures that can be identified from training data. The ROM basically is valid for generic pipe configurations involving 3D unsteady heat transfer and 3D steady flow as long as heat-transfer mechanisms are linearly dependent on the temperature field. Moreover, the training data can be generated by physics-based computational “full-order” models (FOMs) yet also by (calibration) experiments or field measurements. Performance tests using computational training data for a single-pipe configuration demonstrate that the ROM (i) can be successfully identified and (ii) can accurately describe the response of the outlet temperature to arbitrary input profiles for inlet and ground temperatures. Application of the ROM to two case studies, i.e. fast simulation of a small DH network and design of a controller for user-defined temperature regulation of a DH system, demonstrate its predictive ability and efficiency also for realistic systems. Dedicated cost analyses further reveal that the ROM may significantly reduce the computational costs compared to FOMs by (up to) orders of magnitude for higher-dimensional pipe configurations. These findings advance the proposed ROM as a robust and efficient simulation tool for practical DH systems with a far greater predictive ability than existing compact models.

Impacts of retention basins on downstream flood peak attenuation in the Odaw river basin, Ghana

Study regionOdaw River Basin (ORB) in Ghana Study focusWe simulated and examined the impacts of retention basin as a hydraulic structure in attenuating the flood peaks downstream of the ORB with a coupled HEC-HMS and HEC-RAS models for different flood scenarios. Calibrated and validated HEC-HMS models were used to forecast floods in terms of peak flows and results forced into the 2D Unsteady flow HEC-RAS model to simulate flood inundation areas.New hydrological insight for the region: The calibrated and validated HEC-HMS model indicated good performance (NSE > 0.65) in simulating the runoff characteristics of the basin. Forecasted peak flows with the calibrated model for return periods of 30-to-1-year were 131.1 m3/s, 121.6 m3/s, 106.4 m3/s, 88.8 m3/s and 59.3 m3/s respectively for the “without” a retention basin scenario within the ORB. In the “with” retention basin scenario, attenuated peak flows were observed downstream the ORB by 8.1 % (120.5 m3/s), 8.4 % (111.4 m3/s), 9.1 % (96.7 m3/s), 13.6 % (76.7 m3/s) and 13.2 % (51.5 m3/s) respectively for the different return periods. Flood volumes reaching downstream of the basin reduced by 2.3 %, 2.5 %, 2.7 %, 3.0% and 3.8 % respectively due to the presence of the retention basin. The retention basin increased the basin lag time by an average of 4 h across all different flood scenarios. The introduction of retention basins will serve a pivotal role in flood management and planning in the ORB.

THERMAL RADIATION IMPACT AND CATTANEO-CHRISTOV THEORY FOR UNSTEADY FLOW OF MAXWELL FLUID OVER STRETCHED CYLINDER WITH INCONSISTENT HEAT SOURCE/SINK

Examination of thermal and solutal energy with sophisticated guesstimate of thermal radiation bearing. Conveyance portents in Maxwell fluid pour thru the gain of Cattaneo-Christov double diffusion theory is fulfilled in this artefact. Unsteady 2D flow of Maxwell fluid with variable thermal conductivity over the stretching cylinder with thermal emission and heat source/sink is deliberated here. We verbalize the partial differential equations (PDEs) under particular molds for the governing physical tricky of heat and mass transportation in Maxwell fluid by using double diffusion of Cattaneo-Christov model rather than classical Fourier's and Fick's law. Numerical technique $4^{\text {th }}$ order Runge-Kutta method is employed for the solution of ordinary differential reckonings (ODEs) which are obtained from governing PDEs under the apt resemblance transformations. In the interpretation of acquired fallouts, we beheld that for fitting upshots the tenets of unsteadiness constraint should be less than one. The higher tenets of Maxwell parameter deteriorations the flow field but increase the energy transport in the fluid flow. Both temperature and attentiveness scatterings in Maxwell liquid deterioration for sophisticated tenets of thermal and attentiveness relaxation time constraint. Alike, trifling thermal conductivity constraint also augments the temperature field. Auxiliary, the rate of heat transfer deteriorations.

Numerical and experimental investigation of 3D unsteady flow fields of a low head axial flow turbine under different blade number

Low-head axial flow turbines (LHAFT) are important turbomachines suitable for converting low-head water (potential energy) into mechanical (kinetic) or electrical energy. The performance characteristics of this kind of turbine are an essential aspect of its design and operational life cycle. Nevertheless, pressure fluctuations within the turbine affect its operational reliability. Hence its fluctuation characteristics cannot be overlooked due to its influence on vibration, noise, and severity of performance. It is essential to investigate the zones associated with high unsteadiness and turbulence. Furthermore, blade number and variation in flow rate are other important, influential factors on the level of pressure fluctuations. Given the above, numerical and experimental investigation of pressure fluctuation intensities within the flow channels of the LHAFT model under different blade numbers was carried out in this study. The results posit that the pulsating pressure coefficient decreases gradually from the inflow to the guide vane but increases at the runner, then falls as the flow progresses in the outlet pipe. At the runner, the flow experienced the most irregular flow patterns in the turbine. All three runner cases were operated with nine guide vanes, but after one complete revolution, blade numbers z = 2, 3, and 4 revealed regular pressure fluctuations, respectively, in the stationary part (guide vane, inlet and outlet pipes). Regardless of the case study, nine (9) regular peaks and valleys of pressure pulses matching the number of vanes on the static vane were recorded in the runner flow passage. The flow interaction between the static vane and runner is responsible for the pressure fluctuation, which influences the turbine’s vibration and noise. The obtained results would be an essential reference to noise and vibration analytical studies in turbines to optimize them for improved operational reliability.