Increasing Froude Number Research Articles

Numerical Simulation of Resistance and Flow Field for Submarines near Ice Surface

When a submarine operates in polar regions, the polar environment inevitably impacts its resistance and flow field characteristics, especially when the submarine navigates near the ice surface. This paper investigates the hydrodynamic characteristics of a submarine sailing near the free water surface and the ice surface using computational fluid dynamics (CFD) methods. In order to quantify the impact of ice on the resistance and flow field characteristics of the submarine, the resistance coefficients are calculated for both near ice surface and free surface. The resistance, velocity field, and pressure distribution around the submarine at different depths and speeds are analyzed. The results indicate that the total resistance of the submarine sailing near the ice surface is lower than the free water surface. When the submarine is sailing near the ice surface, its total resistance coefficient decreases with increased submergence depth at a constant Froude number. At a fixed depth, the resistance coefficient also decreases as the Froude number increases. Additionally, when the dimensionless depth relative to the maximum hull diameter (D) exceeds 3.5, it has little effect on the resistance coefficient.

Peristaltic flow under the effects of tilted magnetic field: enhancing heat transfer using graphene nanoparticles

ABSTRACT This study investigates the consequences of inclined magnetic field and thermal radiation on peristaltic transportation of nanofluid through a porous media. The nanoliquid is composed of graphene nanoparticles and water. Viscous dissipation, mixed convection, thermal radiation, Joule heating and gravity effects are also considered. Mathematical modeling is carried out under small Reynolds number and large wavelength approximations. Resulting system of equations is numerically solved through built-in command NDSolve through Mathematica. The purpose of this research is to investigate the impact of volume fraction of nanoparticles, phase difference, inclination angle of the applied magnetic field, geometry parameters, Hartmann, Darcy and Brinkman numbers on axial velocity, temperature profile, heat transfer rates at the boundaries, pressure gradient, and pressure rise per wavelength. Outcomes of this study reveal that the addition of graphene nanoparticles enhances heat transfer performance. Velocity profile reduces and temperature increases for greater Hartmann number. Moreover, higher values of Hartmann number enhance heat transfer performance and peristaltic pumping. The enhancement of Darcy number increases velocity, temperature, and pressure while decreasing the peristaltic pumping. Variation in thermal radiation parameter reduces the temperature profile. The rate of pumping and pressure gradient decreases on increasing Froude number.

Electrohydrodynamic peristaltic microfluidic flow with thermal and molecular analysis featuring sloped configurations

This study examines the simultaneous impacts of thermal and molecular transfer of non-Newtonian fluid propelled by the collective impact of electroosmosis and peristaltic pumping via inclined channel. Internal frictional heating and heat generation are also taken into consideration. The electrohydrodynamic phenomenon is described by the nonlinear Poisson–Boltzmann equation. The problem is modulated mathematically through a system of coupled non-linear differential equations in wave frame of reference. Using the regular perturbation method around a small wave number δ, we obtain sequential solutions for stream function ψ, electric potential ϕ, velocity u, pressure gradient dpdx, temperature θ and concentration Ω distributions. The influences of newly arising parameters such as the electroosmotic parameter me, relaxation time parameter λ1, retardation time parameter λ2, wave number δ, Reynold’s number Re, heat generation parameter β, Prandtl number Pr, Schmidt number Sc, Froude number Fr and Soret number Sr on physical characteristics are analyzed graphically. There is an inverse correlation between the parameters of relaxation time and retardation time and their effects on axial velocity, concentration, and temperature distributions. In particular, the temperature of the fluid increases as the EDL parameter, relaxation time parameter, viscous dissipation parameter, and Reynolds number increase, but decreases as the retardation time parameter increases. Moreover, the axial pressure gradient increases as Reynolds number and inclination angle increase, while it decreases as Froude number increases. The current model has applicability in the chemical industry, reservoir engineering, micro-fabrication, and biomedical applications, where electroosmotic effects on heat and mass movement are crucial.

Bragg scattering by an irregular versatile seabed in the presence of current

The Bragg scattering due to an undulated elastic bottom in the presence of a uniform current is discussed in the present paper. The conditions of Bragg resonance are derived analytically and discussed numerically for various values of physical parameters. The mathematical techniques used for discussing the analysis are the perturbation and Fourier transform methods. It is seen that the amplitude of the Bragg reflection increases with the increase in the flexibility factor in the versatile floor of the sea, and there is a significant impact of the current speed on Bragg reflection and transmission coefficients. The maximum value of the amplitude of Bragg reflection is observed to decrease as the Froude number increases. Again, it is seen that the transmitted energy produced in the presence of uniform current does not fluctuate considerably when the nature of an elastic bottom gets closer to that of a stiff floor. The blocking resonance in the presence of current and elastic bottom is analyzed by neglecting the small bottom undulation. A significant effect of blocking resonance on Bragg reflection and transmission is observed.

Impact dynamics of granular debris flows based on a small-scale physical model

The peak pressure of a granular debris flow at low Froude conditions can be calculated with knowledge of the stress anisotropy and the bulk density as well as the run-up height at impact. Based on a small-scale physical model, measurements of stress anisotropy and flow density values at impact are presented and applied to existing run-up prediction models, and further compared with back-calculated run-up coefficients from measured maximum impact pressures. For this purpose, we conducted 17 experiments with impact measurements and six experiments without impact measurements at Froude numbers, ranging from 0.84 to 2.41. Our results indicate that run-up heights are best reproduced by predictive models, either based on energy or mass and moment conservation, when anisotropic stress conditions, found in this study to range from 1.2 to 5.0, and bulk density variations due to impact, ranging in this study from 0.8 to 2.3, are considered. The influence of stress anisotropy and density variation on the run-up prediction differs, depending on the modelling approach. For the calculation of run-up heights based on the energy conservation concept, the influence of stress anisotropy becomes more significant with increasing Froude number, whereas for models based on mass and momentum conservation, bulk density variations have a greater influence on the estimation of the potential run-up.

Numerical Analysis on the Flow Depth Behaviour in Dividing Open-Channel for Trapezoidal and Rectangular Cross-Sectional Channel

Open-channel with dividing flow refers to any side water withdrawals from streams, rivers or main channel. It has become an important issue, especially when measuring the flow rate and depth of water as part of environmental management schemes and many practical projects such as the system of irrigation and drainage, water and wastewater treatment plants and other water resources projects. Although the behaviour of water flow has been studied by the previous researchers, most studies have only been carried out in simulation and lab experiment for a straight prismatic main channel. The mathematical research has not yet been fully understood, particularly in relation to the behaviour of water flow. Therefore, in this study, the modified general equations of dividing open-channel flow for rectangular and trapezoidal in the form of non-linear polynomial equations are proposed to determine the upstream flow depth in rectangular and trapezoidal cross-sectional channel. The computations of water flow depth influenced by Froude number and discharge ratio are performed with Newton-Raphson procedure in Maple software. The numerical solution shows the good agreement with the experimental data as reported in the literature. When the discharge ratio is low, the flow depth in trapezoidal and rectangular channels exhibits similarity. However, as the discharge ratio increases, the flow depth in the rectangular channel surpasses that in the trapezoidal channel. Furthermore, as the Froude number increases, the rectangular channel experiences a greater flow depth in comparison to the trapezoidal channel.

Effect of lateral confinement on wave generation and attenuation induced by granular debris

ABSTRACT The lateral confinement effect significantly influences wave amplitude at the generation and propagation stage. A series of physical experiments and numerical simulations considering different parameters was conducted to study the effect of lateral confinement on waves, and the enlargement percentage from lateral confinement on the maximum wave amplitude has been estimated and validated. Results indicate that sliding mass is the most significant factor influencing the wave amplitude on wave generation, with an average influence ratio of 19.0%, and there is a lower influence ratio of 12.3% for particle size parameter. The enlargement percentage induced by lateral confinement decreases from 55.0% to 31.1% on wave generation location as the slide Froude number increases. On the location of wave propagation, the enlargement percentage increases as the slide Froude number increases, ranging from 17.4% to 47.7%. Equations of the enlargement percentage are presented in this study to align the maximum wave amplitude when physical experiments are influenced by lateral confinement.

Numerical Study on Resistance of Stepped Planing Hull

A stepped planing hull, also known as a step hull, is a hull modification that reduces the wetted surface area. Although this type of hull has proven effective in several ships, it is still rarely used. The step hull possesses numerous advantages that make it ideal for activities involving small and fast boats. However, regrettably, its full potential remains untapped at present. The purpose of this study was to identify the effect of variations in the angle of the step hull on resistance or drag. The study utilized the CFD method, and three hull configuration models were used at each change in hull step angle of 180º, 210º, 240º, and 270º. Configurations 1 and 2 have similarities in terms of rear hull length (600 mm), hull height (20 mm for configuration 1 and 30 mm for configuration 2), and deadrise angle (15° for configuration 1 and 20° for configuration 2). Configuration 3 has similarities with an 800 mm rear hull, 20 mm hull height, and 15° deadrise angle. It was found that as the Froude number increases, the coefficient of total resistance decreases. Conversely, as the Froude number increases, the resulting resistance also increases. The configuration with the highest resistance value corresponds to the alteration from configuration 2 with a hull step of 180°, and that the alteration from configuration 2 with a hull step of 270° corresponds to the configuration with the lowest resistance value. This study concludes that deadrise angle and the height of the step hull are the main factors that require careful consideration when designing ships that use a step hull. Therefore, this research provides an understanding of the step hull and can serve as a basis for the development of the step hull.

Experimental study on insertion loss of air bubble layer in freestream flow

Air injection in water has several engineering advantages, such as an air lubrication system, cavitation control, and noise reduction. The present study investigates the effect of air injection rate and stream velocity on bubble layer volume fraction, thickness, and noise mitigation. The air bubble volume fraction is controlled through the injection rate of 2 to 25 SLPM at different stream velocities. The Froude number is in the range of 30.30 to 70.7. The image processing technique quantifies the air bubble projected void fraction and thickness. The air is injected through a multi-hole pipe placed on a modified NACA 0010 hydrofoil with a 100 mm chord length. The acoustic measurement system consists of a sound transmitter that projects sound waves at the frequency range of 7 to 50.5 [kHz], and on the opposite side of the air bubble layer, a hydrophone is placed to receive the transmitter sound wave. The results showed that the air bubble projected void fraction increased as the air injection and Froude number increased. Higher stream velocity promotes air bubble breaking and the formation of diverse air bubble patterns such as mono-dispersion bubbles and clustering bubbles. As the Froude number increases, the size of the bubble decreases. At various air injection rates and stream velocities, the thickness of the air bubble layer is found to be nearly constant. The bubble layer effectively reduces the noise in all frequency ranges of the present study. The sound pressure level (SPL) inhibition rate increases as the air bubble projected void increases. The insertion loss increases with stream velocity as higher flow velocity leads air bubbles to break and form a cluster of air bubbles, which is found to be more effective in reducing noise than a single bubble. Regardless of injection rate, the maximum insertion loss is 44 [dB] in a frequency of 20 [kHz] and Froude number 70.7.

Аналитическое решение задачи определения границы растекания потока

A mathematical model of a two-dimensional high-speed flow in terms of justification and taking into account several physical assumptions is formulated. The problem is solved analytically in the plane of the velocity hodograph and in the physical plane to determine all parameters in terms of flow flow. The coupling of a uniform flow with a general flow in the form of a "simple wave" made it possible to achieve a reduction in the error of the mathematical model. The adequacy of the pre-sented method is shown.
 The existing models are described that are insufficiently acceptable and adequate in terms of the geometry of the flow boundary, but with a large mismatch in local depths and velocities. The adequacy of the new model as a whole is characterized by the convergence of the model parameters both in geometry (flow spreading boundaries) and kinematics (depth and flow velocity) increased to 18% in both directions.
 The section of the "simple wave" should be well combined with the real flow, taking into ac-count the forces of resistance to the flow. The boundaries of the use of the proposed model belong to the section of the expansion of the flow in 3-7 b as required in the reference literature, and have been clarified in earlier works. The proposed model, as shown in the article, takes into account real (experimental) flow spreading and is consistent with previously performed theoretical studies. An important conclusion in the article is that the values of the Froude criterion in the new model can be any in the range from 1 to infinity, and at the same time the section "$X_D^I$" can increase with in-creasing Froude number.

Characteristics of the surface signatures induced by a sphere in a linearly stratified flow

Internal waves generated by a moving body submerged in a stratified fluid typically yield modest surface signatures. Large-eddy simulation (LES) is employed to capture the surface signatures generated using a moving sphere in a linearly stratified fluid with various Froude numbers (Fr) and diving depths (D). For surface Kelvin wakes, with increasing Froude numbers (Fr), the wake angle (θ) decreases, the wavelength (L) and the maximum surface wave amplitude (Amax) increases. Within the range of our simulation, the influence of diving depth (D) on wake angle (θ) and wavelength (L) is insignificant, while the maximum surface wave amplitude (Amax) decreases as diving depth (D) increases. Additionally, surface turbulent signatures characterised by horizontal divergence (divh) are identified in the near wake. The results demonstrated the following: the horizontal divergence (divh) is transported upstream and downstream from internal wakes to the free surface, whereas the vertical vorticity (ωy) is only transported downstream. And the horizontal divergence (divh) can be transmitted for a larger distance than the vertical vorticity (ωy).

Discharge coefficients formulae of grate inlets of complicated conditions for urban floods simulation and urban drainage systems design

With the acceleration of climate change and urbanization, all over the world is widely facing serious urban flooding problems. Grate inlets are key elements for the discharge exchange of surface flows and underground sewer flows in urban floods, so the accurate calculation of the overflow discharges of the grate inlets is related to the accurate simulation of the urban flood evolution process, which also plays an important role in the design of sustainable urban drainage systems. This study investigated the discharge coefficients of six types of grate inlets under different approaching discharges, transverse and longitudinal road slopes through 285 indoor 1:1 tests, mainly focusing on the supercritical flow conditions with less attention before. The experimental results show that: (1) With all other parameters being equal, as the interception discharge Q increases, the discharge coefficient increases. When the approaching Froude number increases, the discharge coefficient also decreases. The performance of parallel grate inlets in terms of discharge coefficients is not significantly different from that of vertical grate inlets. (2) Using Buckingham’s theorem of dimensional analysis, 12 groups of accurate grate inlets discharge coefficient calculation formulae were creatively proposed. The average relative errors of the 12 groups of formulae are 0.37% ∼ 5.41%, indicating that the calculated values of the formulae and the measured values are in good agreement. (3) The discharge coefficients of grate inlets were found to show a strong dependence on the Froude number of the approaching discharge, being in agreement with previous study result. But the relative error of individual data in this method is large, so the use of equations with more influencing parameters is recommended. A novel and effective method was also proposed to calculate the interception discharge of the grate inlets by iteration. This study can provide important references for the design and selection of grate inlets for urban drainage systems and also provide support for accurate simulation of urban floods.

The role of blocking dynamics and current on wave scattering due to finite floating elastic plate

The role of wave blocking on flexural gravity wave motion with oblique incidence and current is discussed. The oblique wave incidence due to a finite floating elastic plate is investigated using the eigenfunction expansion method. The role of different wave propagating modes on reflection coefficient is discussed. The reflection and transmission coefficients, the surface elevation, and plate deflection in the presence of current are derived. The effects of flexural rigidity and the uniform current speed on reflection and transmission coefficients are analyzed. The resonating nature of reflection coefficient for some fixed values of plate length is observed. Significant effects of different combinations of wave propagating modes of plate covered regions and open water regions on the reflection and transmission coefficients are observed. The wave energy propagation from reflection coefficient decreases whenever the Froude number increases. It has been found that the amplitude of the plate deflection increases as the value of the Froude number increases. The amplitude and wavelength of the reflection coefficient are higher for the combination of the first propagating mode of the plate covered region and the second propagating mode of the open water region. Moreover, it is found that zero reflection and full transmission occurs periodically. Co-propagating waves are found to transmit more energy while counter-propagating waves reflect more energy. Higher values of flexural rigidity result in reduced wave energy transmission.

Analysis of influencing factors of the projectile entering the water through the ice hole

The ice hole, as a special constraint environment, affects the dynamics of water entry. In this paper, the finite volume method (FVM) is used to study the cavity dynamics of the projectile passing through the ice hole. The results show that the cavity evolution law of the projectile passing through the ice hole is different from that of the projectile entering the water freely, and the backflow of the splash crown occurs near the hole. As the Froude number (Fr) increases, the time when the splash crown flows back at the hole is earlier, and the time when the cavity pinch-off occurs at the tail of the projectile is also earlier. The fluctuation of force decreases, and the velocity variation becomes more stable as the Fr decreases. After the projectile with a large aspect ratio passes through the ice hole, the cavity collapse becomes more obvious, and the resistance increase. The constraint effect of the hole on the cavity strengthens as the hole thickness increases, and the cavity integrity after the pinch-off becomes worse. After the projectile passes through the hole, the resistance and force fluctuation increase as the hole thickness increases.

Estimating Manning’s coefficient n for sheet flow during rainstorms

Many hydrological and soil erosion models employ Manning’s coefficient (n) to calculate the velocity of sheet flow (SF). However, Manning’s coefficient of SF cannot be estimated accurately due to the strong influences of rainfall, slope gradient, ground surface roughness, sediment size, etc. The effects of rainfall, especially rainstorms, on Manning’s n are usually ignored. In this study, flume tests were conducted with rainfall intensities ranging from 40 to 120 mm h−1, unit width inflow discharges ranging from 0.02 to 0.06 m2 min−1, bed surface roughness values ranging from 0.009 to 0.25 mm, and slope gradients ranging from 3° to 7°. Manning’s n and the correction (Δnr) induced by raindrops were calculated. The results indicated that Manning’s n without rainfall increased with increasing surface roughness and decreasing unit width inflow discharge. In rainstorms, Manning’s n increased with increasing rainfall intensity and surface roughness and decreasing unit width inflow discharge. Δnr increased with increasing rainfall intensity and surface roughness and decreased slightly with increasing unit width inflow discharge. Manning’s n significantly decreased with increasing Froude number (Fr) according to a power function, while Δnr significantly decreased logarithmically with increasing Fr. The Δnr values of this study were greater than 0 when Fr was less than approximately 2.15. For slope gradients of 3°, 5° and 7°, the rainfall increased n by 1.47–49.33 %, 0.44–21.81 % and 0.43–23.94 % for the cases of Fr < 2.15, respectively. This result indicates that the effects of rainfall on Manning’s n of SF cannot be ignored for laminar flows and low Reynolds numbers (<900). Additionally, two empirical equations for predicting Manning’s n and Δnr under rainfall conditions were devised. The correction Δnr due to raindrop impact was affected by the inflow or base flow regimes. This study experimentally provides basic insights into the effects of rainfall on Manning’s coefficient.

Propagation Mechanism of Deep-Water Impulse Waves Generated by Landslides in V-Shaped River Channels of Mountain Valleys: Physical Model of Regular Rigid Block

Landslide-induced impulse waves in alpine valleys are a significant risk to large-scale dam and reservoir engineering projects in the surrounding area. In this study, a 1 : 200-scale physical model of landslide-induced impulse waves in a V-shaped river channel was established, and 18 groups of tests were conducted to evaluate the influence of different parameters, such as the volume and shape of the landslide body, water entry velocity, and water depth of the reservoir. Based on the test results, a dimensionless formula was established for the first wave height of impulse waves caused by a deep-water landslide in a V-shaped channel. An energy conversion law was determined for the impact of landslide-induced impulse waves on the reservoir bank. Finally, a distribution law was obtained for the initial maximum pressure caused by landslide-induced impulse waves along the water depth on the opposite bank. The theoretical predictions of the dimensionless formula showed good agreement with the experimental results, and the energy conversion rate of the landslide-induced impulse waves initially increased and then decreased with an increasing Froude number. The maximum dynamic water pressure showed a triangular distribution with increasing water depth below the surface of the still water body. The impact pressure of the impulse waves on the slope on the opposite bank increased with the water entry velocity. This study provides a scientific basis for the risk prevention and control of landslide-induced impulse waves in river channels feeding into reservoirs.

Free-surface undulation and velocity turbulence in shallow undular hydraulic jumps

Undular hydraulic jumps and bores occur in coastal and estuarial regions at small approach Froude numbers and introduce non-uniform evolution of hydraulic properties in the flow direction, affecting the transport and deposition of sediment and other materials. This paper reports an experimental study of relatively wide undular hydraulic jumps generated in a 1.4-m-wide flume, characterized by inflow aspect ratio less than 0.06 and no lateral shockwave crossing at the first standing wave crest. General free-surface shape observations were conducted for a range of Froude numbers between 1.5 and 2.9 and Reynolds numbers between 2.5 × 104 and 1.2 × 105, while detailed free-surface and velocity measurements were performed at longitudinal and transverse cross-sections using acoustic displacement meters (ADMs) and an acoustic Doppler velocimeter (ADV), at five Froude numbers from 1.5 to 1.9. The results highlight complicated relationship of the three-dimensional free-surface characteristics with the variation of Froude number, which exhibits different features at the first two waves and at other sequent waves. The velocity data highlighted unique features of turbulent velocity redistribution at the first wave, including the distributions of turbulence intensity and Reynolds shear stresses. Particular focus on the formation of a “quiet water” zone below the upward-deflected mainstream flow was reported, with presence of instantaneous reversing velocities above the channel bed. The flow pattern analysis was facilitated with mean vorticity characterization. The results reflect that the evolution of undular hydraulic jump with increasing Froude number is a process of gradual turbulence localization towards the first standing wave, and the transition to a breaking hydraulic jump is achieved by the formation of a surface roller at the steepened jump front overwhelming the “resistance” of the bottom “quiet water” zone and forcing a change in the main flow path.

Influencia de la geometría de entrada en tomas sumergidas sobre la sumersión crítica para la formación de vórtices que arrastran aire

RESUMEN Se realizó un estudio experimental para estudiar la influencia de la geometría de una toma horizontal sumergida en la formación de vórtices de superficie libre que arrastran aire. Se ensayaron dos tipos de perfiles de ingreso a la toma: perfil acampanado y de arista viva. En un gráfico adimensional, en el que la sumersión relativa se expresa en función del número de Froude, se delinearon para cada caso las regiones en las que no se formaron vórtices con arrastre de aire. Se determinó el tipo de vórtice para cada punto y se delinearon las regiones donde no se forma ningún vórtice. Se comprobó que, a medida que aumenta el número de Froude, es necesaria una mayor sumersión relativa para evitar el ingreso de aire hacia la toma sumergida. Además, la toma de arista viva requirió una mayor sumersión relativa que la toma de perfil acampanado, en el rango de número de Froude ensayado, para evitar la formación de vórtices que atrapen aire. Se comprobó, en los vórtices de tipo B, que los periodos de ingreso de aire eran más prolongados cuando se instalaba una toma de arista viva para las mismas condiciones hidráulicas que para la toma de perfil acampanado.

Study on high-speed water entry of the projectile passing through an ice hole in a low-temperature environment based on a modified thermodynamic cavitation model

It is a complicated problem to study high-speed water entry of a projectile passing through an ice hole in a polar environment. This involves the constraint of the ice hole on the free surface and low-temperature cavitation during the water entry. In this paper, a numerical method involving a modified thermodynamic cavitation model is introduced to study the water entry process. The numerical method is validated by comparing the numerical results of cavity evolution with the experimental data. The cavity dynamics of the projectile passing through the overwater ice hole at high speed and different ambient temperatures are studied. The cavity evolution, flow field, and motion state of the projectile are analyzed. The results show that a nested cavity forms when the projectile passes through the ice hole at high speed. The drop in temperature accelerates the surface closure and deep pinch-off. The effect of the temperature on cavity evolution weakens as the Froude number (Fr) increases. Moreover, at high Fr, the temperature alters the appearance of the ripple on the cavity surface and the growth trend of the cavity size. The drop in temperature reduces the content of the vapor in the cavity and changes the flow characteristics. At a low temperature, the hydrodynamic drag of the projectile passing through the ice hole increases, and the pressure distribution on the surface of the projectile is different.

Investigation of Hydraulic Conditions and Shape of Flip Bucket Spillways on Cavitation Phenomenon by Considering Dynamic Pressures

Abstract Cavitation is one of the destructive phenomena which occurs in hydraulic structures and can cause considerable damage to them. This phenomenon is likely to take place in parts of hydraulic structures where the flow velocity is high and water pressure is below the water vapor pressure, thereby leading to the formation of cavitation bubbles. Dynamic pressures may, frequently and in short time periods, reduce flow pressure to below the vapor pressure of water and form cavitation bubbles as a result. Taking dynamic pressures into account, this study examines the potential for the occurrence of cavitation in flip bucket spillways. This research is based on experimental studies and it focuses on the cavitation phenomenon by measurements of pressure fluctuations along flip bucket spillways with different geometrical characteristics. Measurements of dynamic and statics pressures on three different models of flip buckets were made within a range of different Froude numbers. Using statistical analyses on pressure fluctuations, this study has obtained the equivalent pressures of the 0.1% incidence probability, which, in turn, have been used, along with static pressures, for calculating the cavitation. Results show that as the Froude number increases (from nearly five to almost ten), the cavitation index decreases, and after that, the trend of cavitation index is reversed and starts to rise. Also, it is demonstrated that the cavitation probability on inlet and outlet scope of the flip bucket is higher than the middle part. Hence, cavitation incidence probability increases while the ratio of width to radius of the bucket rises.