Number Fr Research Articles

Flow Resistance Coefficient Under Rigid Vegetation Coverage: An Experimental Study

ABSTRACTRigid vegetation is prevalent in the Loess Plateau region. Most simulation studies assume that vegetation grows perpendicularly to the slope surface (BS), overlooking the influence of growth perpendicular to the horizontal plane (BH) on the slope flow resistance coefficient. Therefore, this study explores the effects of rigid vegetation on the slope flow resistance coefficient by conducting indoor simulated scouring experiments under different vegetation coverage (0–15.89%), two growth directions (BS and BH), four slopes (5°, 10°, 15° and 20°), and five flow rates (5, 10, 20, 30 and 40 L·min−1). The results showed that the resistance coefficient increased non‐linearly with vegetation coverage; however, the growth rate slowed with increasing slope at high coverage, showing a decreasing trend. The resistance coefficient under BS conditions was generally higher than that under BH conditions. As the coverage increased (0–15.89%), the resistance coefficient under BS conditions became 1.51–1.99, 1.1–1.26 and 1.52–1.59 times that under BH conditions. The resistance coefficient ratio negatively correlated with the flow rate and water depth and positively with the slope. Furthermore, the relationship between the Reynolds number (Re) and resistance coefficient under BS and BH conditions significantly differed, with a negative correlation under BS conditions and a positive one under BH conditions. The Froude number (Fr) exhibited a strong negative correlation with the resistance coefficient, and the impact became more significant as vegetation coverage increased. Through dimensional analysis and nonlinear fitting, a high‐precision resistance coefficient prediction model (adjR2 = 0.98, NSE = 0.99, RRMSE = 0.04) was developed, which provided theoretical support for engineering designs and enhancing soil and water conservation strategies on the Loess Plateau.

Analysis of forces on nodules during Coandă-effect-based hydraulic collection

The nodule pickup device is a crucial component of a deep-sea mining system. It is widely perceived that leveraging water flow for the separation and retrieval of nodules is a promising approach. A series of experiments and numerical simulations were conducted to examine the impact of non-dimensional parameters on the force characteristics and flow field of the particle in Coandă-effect-based hydraulic collection. The results showed that the lift coefficient of the particle initially increased before subsequently diminishing from the jet nozzle to the rear. Notably, the lift coefficient α reached its maximum at the convex curved surface between x/d = −0.17 and 0.33. Furthermore, a distinct linear correlation was established between the maximum lift coefficient αmax and Froude number Fr across varying h/d, and an empirical formula for predicting the lift coefficient was developed through data fitting. Upon experimental validation, the prediction exhibited a maximum error of less than 20%. Additionally, numerical simulations revealed that the particle significantly influenced the flow dynamics within the collection area, and the flow field characteristics and the particle forces can be corroborated with each other. The findings not only provided a reliable quantitative tool for assessing the particle force but also facilitated precise predictions of collection performance, aiding in the selection of optimal operational parameters in deep-sea hydraulic collection.

Numerical Analysis and Experimental Validation of Trimaran and Pentamaran Resistance at Various Separation Distances

Trimaran and pentamaran are multihull types with an odd number of hulls, namely three and five hulls, generally consisting of one center hull and two or four side hulls smaller than the center hull, which can reduce ship resistance. The trimaran and pentamaran have a more complex phenomenon than the monohull, because of the interaction between the main hull and the side hull, which causes interference caused by changes in flow velocity, pressure changes, and wave interactions generated by each hull. The objective of this study is to analyze the resistance of trimaran and pentamaran NPL-4b models with transom-symmetrical hull and separation distances, specifically S/L ratios of 0.2, 0.3, and 0.4. Since a more limited base of experience exists for multihull ships, experimental or numerical modeling techniques are essential for designers. Numeric investigations were conducted using Numeca software, and experiments were performed in a towing tank. Both methods follow ITTC procedures. Furthermore, the numerical analysis with CFD simulation modifies the Navier-Stokes equation using the turbulence model k-ꞷ SST to generate the RANS equation so that unsteady fluid flow problems can be calculated. It can be implemented in predicting resistance in Froude numbers (Fr) 0.2 to 0.6 at the systematic series of trimaran and pentamaran hull shapes at the model scale. The simulation results were compared to experimental data to validate the resistance of the ships. Overall, good resistance was produced by the trimaran and pentamaran in the C configuration at an S/L ratio of 0.4 with a total resistance coefficient CT of 6.60 x 10-3 and 7.37 x 10-3, respectively. The two results are in good agreement, both methods have a discrepancy of 3.70 %. Fluctuations influence the resistance in the wetted surface area (WSA), wave interactions between hulls, ship velocity, and wave propagation in the aft hull.

Enhancing Efficiency in Deep-V Planing Hull Ships: A Study on The Design of Spray Strips to Minimize Resistance

Spray strips are deflectors installed on the hull to decrease the wetted surface area (WSA). By reducing the WSA, the overall resistance of the ship is lowered because it lessens the friction of water flowing against the hull. The purpose of this research is to predict the function of spray strips in an effort to improve ship performance. In this study, the numerical methodology employs the Finite Volume Method (FVM) along with the Reynolds-averaged Navier-Stokes equation (RANS) for resolving fluid dynamics issues. The modeling of the two-phase flow involves the utilization of both the Volume of Fluid (VOF) model and the Eulerian model. The results of this study show that spray strips can reduce the total resistance by about 2.7%. Increasing the number of spray strips can reduce the drag shear value by 3.5%. Spray strips are effective in reducing total drag when the Froude number (Fr) is greater than 1 or when the vessel is in the planing phase. The profile shape of spray strips with dimension 2:1 shows the best performance on ship resistance.

A universal drag model for liquid-solid fluidization: Experiment, data-driven modeling, CFD modeling and simulation

Various industrial applications are performed in liquid-solid fluidized beds where drag force plays a significant role in affecting the expansion characteristics of granular-bed, and then determines the mass/heat transfer performance. This study employs dimensionless learning data-driven modeling method, which is derived from the principle of dimensional invariance, to automatically discover the relationship between the drag coefficient and hydraulic dimensionless numbers from the liquid-solid fluidization data. It is found that the Fr number (=ul2/gds) also plays important role in improving the prediction accuracy of drag model except for Re number (=dsulρl/μl). The proposed data-driven modeling method has desired robustness, and the yielded drag model can be applicable to other liquid-solid systems, such as water-polystyrene spheres and water-coal particles, although it is derived from the fluidization of spherical glass beads in rising tap-water. The proposed drag model can also provide good CFD simulation results that agree very well with the experiment data with the relative error less than 5 %.

Impact of dyke and vegetation on fluid force and moment reduction under sub and supercritical flow conditions

Flooding is the most common natural disaster throughout the world and requires efficient management. Therefore, the current investigation aimed to explore the impact of a composite defense system comprising dyke and vegetation on flow dynamics and velocity reduction. Experiments were conducted in an open channel setup with an adjustable bed slope and transparent sidewalls, and the vegetation model was replicated as real trees such as Eucalyptus trees. The study involved calculating several parameters, including flow velocity, reduction of fluid force index (RFI%), reduction in moment index (RMI%), and hydrostatic and hydrodynamic forces. These calculations were done by changing the channel bed slope and keeping the flow rate (discharge) constant while considering both subcritical and supercritical flow conditions. Moreover, regression analysis was performed for the prediction of RFI% and RMI% under various flow conditions. Also, statistical analyses were performed to assess the effectiveness of the defense system in reducing fluid force and moment indices. The result of the current investigation indicates that the highest values of RFI% and RMI% under subcritical flow conditions were 79% and 88%, while under supercritical flow conditions they were 94% and 78%, respectively. Moreover, a velocity reduction of 69% was observed under subcritical flow, while 84% was observed under supercritical flow conditions. Under subcritical flow conditions, RFI% and RMI% enhanced by enhancing Froude number (Fr) because of an increase in velocity reduction and hydraulic jump formation. Similar trends were observed under supercritical flow conditions, with effective mitigation of high-velocity flows by the composite system. The finding of current research helps in providing effective techniques for flood management.

Using froude and weber numbers to represent the changes in the flow pattern from stratified to stratified-wavy or plug for wire-on-tube condenser

According to manufacturing data, a theoretical study of condensation inside a heat exchanger with wires on tubes.examined flow patterns with variable refrigerant mass flow rates. Wire-on-tube condensers are adopted with tubes, which have multiple diameters (3.25, 4.83 and 6.29 mm). In addition to the use of two refrigerants (R-134a, R-600a) working at condensing temperatures of (54.4, 45, and 35 °C). The Equal Equation Solver software (EES) was used to obtain the results for the mass velocity range from 8 to 167 kg s−1m−2. Using the non-dimensionless numbers, the model determines the refrigerant flow pattern. Weber number (We) and Froude number (Fr) were used for mass velocity in a range below 100 kg s−1 m−2, which is recommended flow inside the wire-on-tube condenser. The initial transition of the two-phase flow pattern from stratified to stratified-wavy occurred at beginning of condensation for the quality range (0.78-0.42) was Fr (2.7-2.0) and We (6.1-4.0) for R-134a, while the quality range (0.85-0.39) was Fr (5.0-2.4) and We (7.0-4) for R-600a. Second, as the quality range approached, the stratified-wavy flow was replaced by a plug at quality (0.23-0.06) were Fr (1.5-0.4) and We (3.8-2.1) for R-134a and for R-600a the quality range (0.22-0.05) were Fr (1.7-0.55) and We (3.7-2.2).

Optimization of three-catamaran formation for resistance performance under different Froude numbers and configurations

This study explores optimizing drag reduction in three-catamaran formations under different Froude numbers and configurations. Initially, the numerical methods and models employed in this study are introduced, followed by a grid convergence analysis to ensure the accuracy and reliability of the numerical simulations. The still water resistance of the Delft-372 catamaran is numerically calculated at different Froude numbers (Fr) and compared with experimental data, showing a strong correlation and validating the numerical approach. Subsequently, the flow field and wave height along the hull centerline of the catamaran are analyzed at Fr = 0.3, 0.4, 0.5, and 0.6. Focusing on three-catamaran formations, this study separately investigates the drag characteristics of tandem, parallel, and triangle configurations to reveal the influence mechanisms of different configurations. The computational results indicate that certain formation configurations and distances can reduce resistance for both the entire formation and individual catamarans at different speeds. Additionally, the lateral force, bottom pressure, and bow-stern wave heights experienced by catamarans in formation were analyzed to provide a comprehensive understanding of their hydrodynamic interactions. From the perspectives of drag reduction and safety, the tandem formation is most advantageous, followed by the triangle formation, with optimal spacing recommended for different speeds. To mitigate the adverse effects of lateral force, the spacing between catamarans in parallel formation should exceed 1 B.

The Effect of Tailwater on the USBR Type III Stilling Basin Model

This study evaluates the impact of tailwater on the USBR Type III stilling pond model, which is often used to construct reservoirs with low hydrostatic pressure and small flow rates. The model includes channel blocks, barrier blocks, and end barriers to dampen energy, converting flow from supercritical to subcritical. Hydraulic characteristics, including potential jump types, pressure regimes, and forces on the barrier, are not considered. Any change in discharge during the test also changes the tailwater depth position. The purpose of this study was to determine the effects of tailwater conditions on water height (y1 and y2), pool length (Lj), Froude number (Fr), critical depth (yc), and energy dissipation effectiveness (ΔE). This study shows that the average energy dissipation ratio of USBR Type III Quiet Pool is 87.45% without the effect of Tailwater, with an efficiency rate of 12.55%. When exposed to Tailwater, the average energy dissipation ratio drops to 69.47%, resulting in an efficiency rate of 30.53%. The optimum stilling pond performance is affected by the presence of tailwater (Tw), which reduces the energy dissipation ratio. The depth of the tailwater aids in the dissipation that occurs. Technical abbreviations will be explained in the first use. The water level rise under tailwater conditions exceeds that without tailwater. This finding shows tail water's importance for height rise and flow conditions. Flow conditions with Froude Number (Fr2) values of 0.22 (<1) and Tw are classified as subcritical flow.

Numerical and sensitivity analysis of hydraulic characteristics of triangular labyrinth side weir

Triangular labyrinth side weirs have significantly more discharge capacity than traditional nonlinear weirs, and the complex hydraulic parameter interaction mechanism has been the research focus. This study used Computational Fluid Dynamics (CFD) to analyze the side weir's flow characteristics. Then, the Bayesian optimization algorithm and Extreme Learning Machine (BELM) developed a prediction model for the side weir's discharge coefficient. Finally, Sobol's method performed a sensitivity analysis for hydraulic parameters. The results show that the main channel's streamline is evenly distributed and begins to shift when it is close to the side weir. The overflow front is increasing and secondary flow also increases. BELM's Mean Absolute Percentage Error and Root Mean Square Error are 8.793 % and 0.455 in the testing stage, respectively, declined by about 56.24 % and 32.29 % compared with ELM; Froude number Fr, weir crest angle θ and the ratio of overflow front length to weir head l/h1 are the most critical hydraulic parameters affecting the discharge coefficient, the global sensitivity coefficients are 0.4393, 0.4218 and 0.4152, respectively.

Horizontal buoyant jets into viscoplastic ambient fluids

This study investigates the horizontal injection of a heavy Newtonian fluid into a lighter viscoplastic ambient fluid, in a large reservoir. The flow dynamics is experimentally captured via camera imaging, laser-induced fluorescence, and particle image velocimetry techniques. The flow parameters include various density differences, injection velocities, and ambient fluid viscoplastic properties. Our analysis identifies two key dimensionless numbers, the Froude number (Fr) and the effective viscosity ratio (m), which includes the rheology of the viscoplastic fluid. Our study also examines the effects of these dimensionless numbers on critical jet characteristics, such as bifurcation length, transition length, deviation length, and jet trajectory, and provides correlations using Fr and m, to predict these characteristic lengths. A regime classification based on the bifurcation phenomenon is also presented in the Fr−m plane.

Integrated learning model for water intake capacity of Tyrolean weirs under supercritical flow

ABSTRACT Tyrolean weir can be used as an effective solution to address floatation and sediment deposition in runoff hydropower stations. To improve the efficiency and accuracy of calculating this structure's water intake capacity. The integrated learning algorithm random forest (RF), the firefly algorithm (FA), and the exponential distribution algorithm (EDO) are utilized to develop the algorithm that can be used for the Tyrolean weir Cd and (qw)i/(qw)T prediction models. Sobol's method and SHAP theory are introduced to analyze the above parameters quantitatively and qualitatively. It is shown that EDO-RF is the optimal prediction model for the Tyrolean weir's discharge coefficient and the Froude number Fr has the greatest influence on the Cd prediction results; when Fr < 30, the greater the negative influence of Fr on the model prediction results. When Fr > 30, the greater the positive influence of Fr on the model prediction results. FA-RF is the optimal prediction model for the Tyrolean weir water capture capacity (qw)i/(qw)T, with the ratio of bar length to bar spacing L/e being the largest; When L/e < 20, the greater the negative influence of L/e on the model prediction results. When L/e > 20, the more significant the positive impact of L/e on the model prediction results.

Design and Principles Analysis of Hydrofoil Appendages for Reducing Resistance of High-Speed Ships

To reduce the resistance of high-speed displacement ships with Froude numbers (Fr) between 0.4 and 0.5, this paper proposes the installation of hydrofoils at the bow and stern of the ship. Firstly, starting from the bow wave, this paper proposes the installation of a flat plate appendage at the free surface of the ship’s bow to suppress the height of the bow wave and thus reduce the hull resistance. Taking the DTMB 5415 ship model as the research object, CFD calculation results show that installing a flat plate appendage at the free surface of the ship’s bow can effectively suppress the height of the bow wave, and the total resistance reduction ratio can reach 6.49% when Fr = 0.45. Then, the flat plate appendage was improved to a hydrofoil appendage, further reducing the hull resistance. As a result, the total resistance reduction rate can reach 9.15% at Fr = 0.45. Following this, hydrofoil appendages were installed simultaneously at the bow and stern. The drag reduction effect and mechanism were studied, and the results show that the hydrofoils at the bow and stern have a good drag reduction effect. Suppressing the bow and stern waves and improving the flow field are the main reasons for the drag reduction. Finally, the drag reduction effect of the hydrofoil appendages was verified through experiments, demonstrating its excellent drag reduction effect when Fr = 0.4–0.5 and a maximum total resistance reduction ratio of 14.552%.

Study on the internal waves induced by a submerged body moving in a continuously stratified fluid

This paper studies the characteristics of internal waves induced by the motion of a submerged body through a combination of experimental and numerical methods. First, by deploying an array of conductivity probes in an experiment, the temporal evolution of the internal wave at the plane of the conductivity probe array is obtained and compared with numerical simulation results based on the Navier–Stokes equations, thereby validating the accuracy of the Computational Fluid Dynamics (CFD) model. Subsequently, utilizing CFD calculations, further exploration is conducted on the spatiotemporal distribution characteristics of the internal wave, encompassing its generation and evolution, velocity field distribution, wake angle, and wave profile features. Finally, the variation of the internal wave with the Froude number (Fr) is investigated, revealing that it varies apparently with Fr, including the wave component, wave mode, wake length, wake angle, wave amplitude, and so on. It is found that when Fr is large, the internal wave converges toward the centerline behind the body, until forming a line. The wave magnitude changes with Fr in four stages, i.e., increasing with Fr from zero in the first stage, reaching a peak and decreasing thereafter in the second stage, then changing little in the third stage, and finally increasing approximately linearly in the fourth stage.

Hydrodynamic and turbulence associated with tidal bore propagation in an amazonian macrotidal system

The study analyzed the hydrodynamic and turbulence characteristics of the Tidal Bore (TB) associated with Sucuriju River Coastal System (SRCS), a macrotidal estuarine system located north of the Amazon River mouth. Two points were sampled using ADCP at a frequency of 0.5 Hz for 13 hours, one at the mouth (P1) and the other upstream (P2). The Tidal Gauge (TG) located at the mouth collected tidal data continuously for three months at a 30-second rate. The instantaneous hydraulic jump velocities (HJ) and the hydraulic jump resultant (HJRES) were calculated for TG. The Tidal Bore Froude Number (Fr), Turbulent Kinect Energy – TKE (q2/2), TKE Production (Pτ), Reynolds stress (τx and τy), and Quantity S were calculated for P1 and P2. Over 70 TB occurrences were identified during spring tides, with the highest HJRES of 2.23 observed in March. The U̅ component showed greater results during ebb tide, reaching 1.48 and 1.00 m s−1 for P1 and P2 respectively, with a rapid current inflow associated with TB. The highest TKE and Reynolds stress parameters were observed during ebb tide, with TKE reaching up to 1.80 J m−3 in P1 and 1.12 J m−3 in P2. After the TB these values decreased to almost zero, resulting in lower energy associate with a rapid increase in water level, indicates a transition from supercritical (Fr>1) to subcritical flow (Fr<1). Based on the Fr value, the TB showed characteristics of a Weak Breaking Tidal Bore / Breaking Bore in P1 (1.2 or 1.3 < Fr < 1.5), and Cross waves / shock waves / undular bore for P2 (1.0 < Fr < 1.2 or 1.3).

Dynamic response characteristics of microchannel evaporator in a mechanically pumped two-phase loop under hypergravity environment

The unique hypergravity environment and severe heat-dissipation requirements of modern fighter aircrafts pose serious challenges to the potential utilization of mechanically pumped two-phase loops (MPTLs), which are an efficient cooling technology. The microchannel evaporator is a key component of the MPTL system, and understanding its startup and operation characteristics is of great significance for design and optimization. In this context, an experimental MPTL system is built and fixed on a rotating platform, which is designed to generate hypergravity ranging from 0 g0 to 15.0 g0 (g0 = 9.8 m·s−2). The dynamic-response characteristics of the temperature, pressure, and flow rates during the startup and operation of the microchannel evaporator under various hypergravity conditions are investigated. The results indicate that different startup modes, namely gradual startup under low hypergravity and overshoot startup under high hypergravity, are achieved on the microchannel evaporator, even if the flow rate and heat flux are not changed, which is completely different from that under normal gravity. These two startup modes can be quantitatively recognized by two dimensionless numbers: the boiling number (Bo) and Froude number (Fr). A larger Bo or 1/Fr, which corresponds to a larger heat flux or hypergravity; both conditions contribute to the startup mode of the microchannel evaporator shifting from gradual to overshoot startup. During the operation of a microchannel evaporator, the competition between the elevated saturation temperature of the fluid and the induced Coriolis and centrifugal forces caused by hypergravity determines the wall-temperature variation of the evaporator. The dynamic wall temperature decreases under hypergravity below 2.5 g0, is stable with small fluctuations under hypergravity from 4.7 g0 to 7.5 g0, and increases for hypergravity larger than 11.0 g0.

Efficient functioning of a sewer system: application of novel hybrid machine learning methods for the prediction of particle Froude number

ABSTRACT Sewer systems are usually built with a self-cleaning system that keeps the bottom of the channel free of sediment to lessen the effects of the constant buildup of sediment particles. Because of this, it is important to accurately predict the particle Froude number (Fr) when making sewer systems. For the prediction of Fr, five different sets of input variables were looked at. For the training and testing of the machine learning (ML) model, we used 10-fold cross-validation methodologies to prevent overfitting. M5Prime (M5P) model as a standalone and Bagging-M5P as a hybrid model were utilized, and the results were compared with the empirical equations proposed in the literature. Models perform best when all input variables are used for training and testing of models. The hybrid BA-M5P model performed better than the M5P model and empirical equations. We performed sensitivity analysis and compared the result based on MAE and MSE value, and we found sediment concentration (Svc) is the most important variable to predict the particle Froude number under non-deposition with deposited bed by best performing model BA-M5P. Hence, for the self-cleaning system, we prefer the BA-M5P ML model with Svc the most required variable.

On the water entry impact characteristics of high-speed vehicle with an Arbitrary Lagrangian-Eulerian method

This paper investigates the fluid-structure interaction process of high-speed vehicles during water entry using the Arbitrary Lagrangian-Eulerian method. Through mesh independence verification and comparison of numerical simulation results with experimental data and empirical formulas, the reliability and accuracy of the computational method are confirmed. The study comprehensively analyzes flow field pressure distribution, cavity evolution characteristics, and vehicle force features, evaluating the impact of water-entry angle, Froude number (Fr), and cavitator dimension. The results indicate that during water entry, the instantaneous impact forces are mainly concentrated on the wetted surface at the bottom of the vehicle and the plane at the head. The peak stress at the entry point is significantly higher than at other locations, and stress waves propagate along the vehicle body, concentrating at the hollow structure due to the structural characteristics. The change in water-entry angle does not significantly affect the decay of Fr for the vehicle, but increasing the water-entry angle leads to an earlier and larger peak stress at the mid-point monitoring location of the vehicle. In addition, the study also found that the stress level increases with the increase of the Froude number, resulting in larger high-stress areas and peak stresses. However, the cavity evolution at the same water-entry depth is essentially independent of the variation in Fr. With the increase in cavitator dimension, the water-entry load and cavity profile will also significantly increase, and vehicles with larger cavitator dimension will generate larger stress waves upon impact.

A coupled computational fluid dynamics-discrete element method modeling for the dynamic behavior of the polar detector in a crushed ice environment during polar exploration

Investigating the dynamic behavior of polar detectors holds significance for the polar exploration of clean energy production. This paper uses computational fluid dynamics and the discrete element method, complemented by laboratory experiments, to systematically explore the water entry dynamics of a projectile passing through a zone of crushed ice accumulation. The research analyzes the influence of different crushed ice accumulation heights (ha) and water entry conditions on cavity formation, flow field distribution, and dynamic characteristics as the projectile passes through the crushed ice zone. Moreover, the influence of multi-body coupling on the movement of crushed ice and fluid is analyzed. The findings reveal alterations in the water entry behavior of the projectile due to the presence of the crushed ice accumulation zone. A notable two-way coupling mechanism between crushed ice and fluid is identified: crushed ice particles influence liquid level fluctuations and cavity evolution, while fluid flow impacts the movement of crushed ice particles. As the height of crushed ice accumulation increases, this coupling effect intensifies, leading to changes in the flow field distribution near the cavity and the hydrodynamic behavior of the projectile. While the alteration in water entry Froude number (Fr) may not significantly alter the evolution pattern of the liquid level flow field, it notably affects the distribution range and formation scale of the flow field characteristics. Additionally, the water entry Fr influences the load characteristics of the projectile as it passes through the crushed ice zone.

Three-Dimensional Numerical Simulation of a Two-Phase Supercritical Open Channel Junction Flow

This study investigates the computational fluid dynamics (CFD) modeling of supercritical open channel junction flow using two different turbulence models: k-ω shear stress transport (SST) and k-ω SST scale-adaptive simulation (SAS), in conjunction with Volume of Fluid (VOF) and mixture multiphase models. The efficacy of these models in predicting the intricate free surface fluctuation and free surface elevation in a supercritical junction is evaluated through a comprehensive analysis of time-averaged free surface data obtained from CFD simulations and Light Detection and Ranging (LIDAR) measurements. The dimensionless Reynolds (Re) and Froude (Fr) numbers of the investigated scenario were Fr = 9 and Re = 5.1 × 104 for the main channel, and Fr = 6 and Re = 3.3 × 104 for the side channel. The results of the analysis demonstrated a satisfactory level of agreement with the experimental data. However, certain limitations associated with both CFD and LIDAR were identified. Specifically, the CFD performance was limited by the model’s incapacity to consider small-scale turbulent effects and to model air bubbles smaller than the cell size while the LIDAR measurements were limited by instrument range, inability to provide insight into what is happening below the water surface, and blind spots. Nonetheless, the k-ω SST turbulent model with the VOF multiphase model most closely matched the LIDAR results.