جستجوی مقالات مرتبط با کلیدواژه « 3D » در نشریات گروه « آب و خاک »

In this study, HYDRUS-2D/3D software was used to estimate the field capacity (FC) and permanent wilting point (PWP) using double-rings infiltration data via inverse solution. For this purpose, the double rings infiltration data obtained from 95 points of different regions in Isfahan were used as model input. The studied soils were classified into seven textural classes including Sandy Loam (SL), Clay (C), Loam (L), Silty Loam (SiL), Clay Loam (CL), Silty Clay Loam (SiCL), and Silty Clay (SiC). For most soil samples, the simulated values ​​of FC and PWP were less than the measured values. The results showed that the lowest error value in estimating FC was related to SL texture (R2 = 0.884 and RMSE = 0.021) and the highest error value for FC estimation was related to Clay texture (R2 = 0.1 and RMSE = 0.122). Furthermore, the lowest and the highest error values for PWP estimation were observed in Loam (R2 = 0.858 and RMSE = 0.003) and Clay (R2 = 0.21 and RMSE = 0.025) soils, respectively. In general, the simulation error increased with increasing clay content in the soil. The estimated PWP values ​​were relatively more consistent than the estimated FC values with their measured values, in all soil samples. Coefficients of determination (R2) were 0.77 and 0.80 for FC and PWP in all soils, respectively. In general, the inverse numerical solution method had acceptable accuracy for estimating FC and PWP, especially in light textured soils.

Probabilistic designation is a powerful tool in hydraulic engineering. The uncertainty caused by random phenomenon in hydraulic design may be important. Uncertainty can be expressed in terms of probability density function, confidence interval, or statistical torques such as standard deviation or coefficient of variation of random parameters. Controlling cavitation occurrence is one of the most important factors in chute spillways designing due to the flow’s high velocity and the negative pressure (Azhdary Moghaddam & Hasanalipour Shahrabadi, 2020). By increasing dam’s height, overflow velocity increases on the weir and threats the structure and it may cause structural failure due to cavitation (Chanson, 2013). Cavitation occurs when the fluid pressure reaches its vapor pressure. Since high velocity and low pressure can cause cavitation, aeration has been recognized as one of the best ways to deal with cavitation (Pettersson, 2012). This study, considering the extracted results from the Flow-3D numerical model of the chute spillway of Darian dam, investigates the probability of cavitation occurrence and examines its reliability. Hydraulic uncertainty in the design of this hydraulic structure can be attributed to the uncertainty of the hydraulic performance analysis. Therefore, knowing about the uncertainty characteristics of hydraulic engineering systems for assessing their reliability seems necessary (Yen et al., 1993). Hence, designation and operation of hydraulic engineering systems are always subject to uncertainties and probable failures. The reliability, ps, of a hydraulic engineering system is defined as the probability of safety in which the resistance, R, of the system exceeds the load, L, as follows (Chen, 2015): p_s=P(L≤R) (1) Where P(0) is probability. The failure probability, p_f, is a reliability complement and is expressed as follows: p_f=P[(L>R)]=1- p_s (2) Reliability development based on analytical methods of engineering applications has come in many references (Tung & Mays, 1980 and Yen & Tung, 1993). Therefore, based on reliability, in a control method, the probability of cavitation occurrence in the chute spillway can be investigated. In reliability analysis, the probabilistic calculations must be expressed in terms of a limited conditional function, W(X)=W(X_L ,X_R)as follows: p_s=P[W(X_L ,X_R)≥0]= P[W(X)≥0] (3) Where X is the vector of basic random variables in load and resistance functions. In the reliability analysis, if W(X)> 0, the system will be secure and in the W(X) <0 system will fail. Accordingly, the eliability index, β, is used, which is defined as the ratio of the mean value, μ_W, to standard deviation, σ_W, the limited conditional function W(X) is defined as follows (Cornell, 1969): β=μ_W/σ_W (4) The present study was carried out using the obtained results from the model developed by 1:50 scale plexiglass at the Water Research Institute of Iran. In this laboratory model, which consists of an inlet channel and a convergent thrower chute spillway, two aerators in the form of deflector were used at the intervals of 211 and 270 at the beginning of chute, in order to cope with cavitation phenomenon during the chute. An air duct was also used for air inlet on the left and right walls of the spillway. To measure the effective parameters in cavitation, seven discharges have been passed through spillway. As the pressure and average velocity are determined, the values of the cavitation index are calculated and compared with the values of the critical cavitation index, σ_cr. At any point when σ≤σ_cr, there is a danger of corrosion in that range (Chanson, 1993). In order to obtain uncertainty and calculate the reliability index of cavitation occurrence during a chute, it is needed to extract the limited conditional function. Therefore, for a constant flow between two points of flow, there would be the Bernoulli (energy) relation as follows (Falvey, 1990): σ= ( P_atm/γ- P_V/γ+h cos⁡θ )/(〖V_0〗^2/2g) (5) Where P_atm is the atmospheric pressure, γ is the unit weight of the water volume, θ is the angle of the ramp to the horizon, r is the curvature radius of the vertical arc, and h cos⁡θ is the flow depth perpendicular to the floor. Therefore, the limited conditional function can be written as follows: W(X)=(P_atm/γ- P_V/γ+h cos⁡θ )/(〖V_0〗^2/2g) -σ_cr (6) Flow-3D is a powerful software in fluid dynamics. One of the major capabilities of this software is to model free-surface flows using finite volume method for hydraulic analysis. The spillway was modeled in three modes, without using aerator, ramp aerator, and ramp combination with aeration duct as detailed in Flow-3D software. For each of the mentioned modes, seven discharges were tested. According to Equation (6), velocity and pressure play a decisive and important role in the cavitation occurrence phenomenon. Therefore, the reliability should be evaluated with FORM (First Order Reliable Method) based on the probability distribution functions For this purpose, the most suitable probability distribution function of random variables of velocity and pressure on a laboratory model was extracted in different sections using Easy fit software. Probability distribution function is also considered normal for the other variables in the limited conditional function. These values are estimated for the constant gravity at altitudes of 500 to 7000 m above the sea level for the unit weight, and vapor pressure at 5 to 35° C. For the critical cavitation index variable, the standard deviation is considered as 0.01. According to the conducted tests, for the velocity random variable, GEV (Generalized Extreme Value) distribution function, and for the pressure random variable, Burr (4P) distribution function were presented as the best distribution function. The important point is to not follow the normal distribution above the random variables. Therefore, in order to evaluate the reliability with the FORM method, according to the above distributions, they should be converted into normal variables based on the existing methods. To this end, the non-normal distributions are transformed into the normal distribution by the method of Rackwitz and Fiiessler so that the value of the cumulative distribution function is equivalent to the original abnormal distribution at the design point of x_(i*). This point has the least distance from the origin in the standardized space of the boundary plane or the same limited conditional function. The reliability index will be equal to 0.4204 before installing the aerator. As a result, reliability, p_s, and failure probability, p_f, are 0.6629 and 0.3371, respectively. This number indicates a high percentage for cavitation occurrence. Therefore, the use of aerator is inevitable to prevent imminent damage from cavitation. To deal with cavitation as planned in the laboratory, two aerators with listed specifications are embedded in a location where the cavitation index is critical. In order to analyze the reliability of cavitation occurrence after the aerator installation, the steps of the Hasofer-Lind algorithm are repeated. The modeling of ramps was performed separately in Flow-3D software in order to compare the performance of aeration ducts as well as the probability of failure between aeration by ramp and the combination of ramps and aeration ducts. Installing an aerator in combination with a ramp and aerator duct greatly reduces the probability of cavitation occurrence. By installing aerator, the probability of cavitation occurrence will decrease in to about 4 %. However, in the case of aeration only through the ramp, the risk of failure is equal to 10%.

In this paper, subsurface flow profiles through coarse porous media have been simulated using a 3-D numerical model with and without surface discharge and their results have been compared with experimental data as well as with analytical solutions. SEEP/3D model, which is based on the finite element method, was used to simulate subsurface flow. The experimental model was consisted of coarse porous media with 6.4 m in length, 0.8 m in width and 1 m in height. The experiments were performed for different boundary conditions with two bed slopes of 4 and 20.3 %. The simulated data of watertableprofiles and seepage discharges were compared with those corresponding experimental data. In no recharge conditions with 4% slope, the numerical data were compared with both experimental and analytical dataindicating that the numerical results underestimated the watertable profilesas compared to the experimental ones. The results was better for the 20.3%-slope. In surface recharge condition, the numerical results only compared with analytical solution of Bear (1972), and the results indicated underestimation as compared to the experimental data.

Cylindrical weir is one of the most common structures for measuring flow rate in open channels. Cylindrical weir is one type of broad-crested weirs that has extensive application due to its stable flow pattern and ease of passing suspended solids. Therefore, in this article, flow over a 7.5 cm diameter cylindrical weir in the rectangular channel was simulated using k-ε turbulence model in three-dimensional flow3D model. Validation was performed with experimental results. The obtained root mean square error of comparison between numerical discharge coefficient and physical values was 0.3427, which represents a good agreement of hydraulic characteristics obtained from numerical and physical models. It was also observed that discharge coefficient value of cylindrical weir was greater than 1.0. Dimensionless ratio of hydraulic head to crest radius was an effective parameter on discharge coefficient, such that its 100% increase enhances discharge coefficient more than 100%. In the numerical model of cylindrical weir, such parameters as velocity, pressure, flow depth and kinetic energy and turbulence were analyzed and compared in some sections of the channel with respect to the weir. Results showed that depth and pressure in the upstream have larger amounts than in the downstream. But, results of velocity were opposite the pressure and hydraulic head. Finally, a relationship was provided for determination of kinetic energy of the flow over the cylindrical weir.

Labyrinth weir is one of the nonlinear hydraulic structures that its geometrical shape increases the discharge coefficient of flow over the weir. In this study, a labyrinth weir, located in a 14.6 m long channel, was simulated and verified using an experimental model with 6 different discharges (15

The discharge coefficient of morning glory spillway is decreased with eddies created by vortex at the inlet part of weir. However, a series of specific blades can reduce vortices which result in the spillway efficiency is increased. Hence, in this research numerical modeling of installed breaker blade on morning glory spillway was evaluated using Flow-3D model. To achieve these purposes, morning glory spillway was modeled without and with blades 3, 4 and 6 blades at 45 degree angle. To simulate the turbulence fluctuations, the modified k-e model (RNG k-e) was used and its results were compared to the experimental data. Results showed that by installing blades, the discharge coefficient increases up to 42 percent with 25 percent decreasing in the upstream water level. Moreover, among the three different arrangements of blades, the six-blade model was found to have more satisfactory results than other models. In comparison to control model, for H/D between 0 to 0.1 and 0.1 to 0.2 the discharge coefficient has been increased 40 and 57 percent for six-blade arrangement, respectively.

Bridges are certainly one of the most important structures but costly service elements in a transport system. The bridges are very required to access the damaged areas in emergency situations such as floods and earthquakes. Scour around the foundations of bridge piers exposed to the flowing water than can destroy the bridge itself is a subject of major concern. Flow pattern is known as responsible for all changes in stream bed. Any obstacle in the channel can form new flow patterns causing additional shear stress exerted on the bed than the equilibrium condition of the absence of the obstacle. Appropriate shaping of flow pattern and proper selecting of pier geometry and the location of bridge piers can be one of the proper methods in reduction of scour amount which is the main subject of the present study.
Inclined bridge group pier is a type of bridges with modern geometry based on development in building technology of structures. Many of these bridges have been built all around the world and the 8th bridge built crossing the Karun River in Ahvaz is a sample of the Iranian ones considered in this research. Hydrodynamic behavior of flow is investigated around the inclined bridge group pier settled on foundation using the FLOW-3D numerical model. Inclined bridge group pier investigated in this study, includes two rectangular piers which are 2.5 cm long and 3.5 cm wide and set in an angle of 28 degree on rectangular foundation which is 16 cm long and 10 cm wide and installed in three different foundation levels namely at, above and below the bed levels. The physical model of prototype pier considered in this study was constructed to the scale of 1:190 of the Ahvaz 8th bridge. In order to verify the accuracy of the numerical model, velocity data obtained from image processing technique were used.
Due to non- linearity and interactions between various phenomena involved, flow pattern around the piers group is entirely different than that for a single pier and consequently the outcomes of the flow pattern around single pier cannot be generalized to the pier group. At all levels of foundation setting, longitudinal component of flow velocity increases surrounding the first pier. The increase in the area and its extension towards downstream is caused by the constriction the flow due to the pier and area rotating of the wake vortex in downstream. When the pier foundation is set at the stream bed, the bed rotating flows extend to a distance between the two piers from near the bed up to the middle of flow depth while in upstream of the second pier and near water surface, the stream lines become parallel to the bed. The comparison of the results of the changes in bed shear stress in the situations of foundation setting in different levels showed that the maximum shear stress occurred when the foundation level is at the bed level and the maximum shear stress exerted on the bed decreases by factors of 17% and 53% in the cases of foundation level to be below and above bed levels, respectively. In addition, the results showed that, the amount of vortex flows increased in upstream piers group and near bed in the case of setting the foundation above the bed. This is because of the fact that the volume of piers group acted as obstacle against flow was more than other level settings. Furthermore, based on the obtained results, in the case of foundation level is set at the bed, the quantity and development zone of vortex flow are much higher than those observed when the setting foundation is below the bed level. This can be attributed to the higher effect of the second pier on the flow pattern being between the first and the second piers. Stream lines turn downward in the range between piers group, and after the collision to bed turn upward to water surface and cause to form rotating flow and hence high turbulence intensity in the area. In the near water surface and the center of group piers, stream lines were observed to be parallel to the bed and caused low turbulence intensity in this area.
The results showed that the levels of setting foundation have a significant effect on hydrodynamic characteristics and flow pattern around the piers. By increasing the dimensionless height of the setting foundation from -1 to 0.5 vortices formed in the downstream piers group is strengthen more and the results from the numerical model are consistent with the results of experimental scour around piers group in all three levels of setting foundations. When the foundation setting is at the bed level, the maximum bed shear stress is observed. The maximum bed shear stress is decreased by factors of 17 and 53 percent when the foundation to be set below and above bed levels, respectively.

Quantitative knowledge of soil water characteristic curve is crucial for modeling water flow and transport processes in agriculture and hydrology. In this study, HYDRUS2D/3D software was used to estimate the hydraulic parameters of van Genuchten-Mualem model via inverse modeling using double-ring infiltrometers. Double-ring infiltration experiment was conducted in three sites with different soil textures (i.e., silty clay, loam and sandy loam) with three replications. Disturbed and undisturbed soil samples were also collected from three depths (0−10, 10−30 and 30−60 cm) per each soil and some soil physical properties such as bulk density, texture, initial water content and saturated water content were measured. Soil water retention curve was determined for the matric suctions lower than 100 cm H2O by sand box, and for the matric suction range 100−15000 cm H2O using pressure plate. The van Genuchten model with Mualem’s restriction was fitted to the soil water retention data by RETC software. The accuracy and reliability of the HYDRUS predictions were evaluated. The results showed that inverse estimation of soil hydraulic parameters provided a reliable alternative method for determining the soil water retention curve at horizon/field scale. The soil water retention curves obtained from the RETC fitting had very good correspondence with those derived from inverse modeling; the efficacy parameters of inverse estimation (i.e., Pearson’s correlation coefficient (r), root of mean squared differences (RMSD, m3 m-3), absolute value of mean differences (AMD, m3 m-3) and the mean difference (MD, m3 m3)) were 0.988, 0.036, 0.012 and 0.008, respectively. Also there was a good agreement between the water content values measured in the soil profile and those predicted by HYDRUS (R2= 0.936).

Scour generation and its development around bridge piers are the main causes of bridges damage and failure. Understanding the scour mechanism is essential to predict the scour and equilibrium scour hole status around bridge piers. In the recent decades, the use of compound bridge piers instead of the simple piers in construction of bridges, has been developed. In this study, using the FLOW-3D software, process of the formation and development of the scour around bridge pier with compound geometry has been investigated. Numerical results obtained from this model were compared with available experimental data. The results showed that this model had the capability to predict the threedimensional flow field and could effectively provide a better understanding of the experimental studies. The results also indicated the complexity of turbulent flow near pile cap so that these flows were deflected in all directions. On contrary to the simple pier, in which the positive maximum velocity occurred in the sides of pier, in the case of piers with compound geometry this velocity occurred in the center of the pier and downstream of the pile cap.

Weirs have widely been used for the flood flow, flow measurement, flow diversion and control of water levels in dams, rivers and open channels. This study was curried out to investigate the hydraulic characteristics of flow over the sharp-crested triangular plan form weirs for different apex angles. Three-dimensional flow field over the weirs 30, 60, 150 and 180 degrees was numerically simulated based on the RNG turbulence model using the software Flow-3D version 10.0.1. The results showed as the apex angle increases, the interference of the longitudinal and lateral falling flows decreases and in turn leads to less disturbance and vortex flow. Also, in downstream, the flow surface knob of the longitudinal profile and height difference between the transverse cross-section profile becomes less and velocity and Froude number increase, whereas the pressure on downstream bottom decreases. The results show that the RNG turbulence model for determining water surface profiles along the channel downstream of the weir of appropriate accuracy.

Examining the properties and behavior of the flow in the rivers and its associated structures is one of complex phenomena that make the use of software inevitable. First, the results of laboratory test carried out by Duan et al. (2009) in Minnesota university, are used verification and comparison of numerical simulations of FLOW-3D(version 9.3). The vertical spur dike was first simulated to verify the model results and the inclined spur dike with 60° and 30° to the flow direction was then considered. The simulation performed with FLOW-3D, for 650 seconds using turbulence models (k-ɛ, RNG, LES). By comparing different turbulence models with experimental results, the maximum scour depth at the tip of the spur dike was 8.82 cm. Then the maximum scour depth calculated by FLOW-3D in the turbulence models of (k-ɛ, RNG, LES) was 9.1, 8.9, 9.1 cm. So the error in RNG turbulence model is about 9 %, compare to the turbulence model k-ɛ, and of LES shows more agreement. In the simulation, the maximum scour depth at the tip of the spur dike 60° and 30° was 8.75 and 6.5 cm respectively.

One of the important purposes of river engineering science is to protect river banks from erosion phenomenon and to prevent shifting of the main channel path. Spur dike is a hydraulic structure which has a lot of applications for stabilizing river banks and increasing water depth. According to widespread use of this structure, it is important to understand the flow pattern around it. Since flow pattern around a spur dike is complex and fully 3D, 3D simulation was done in this study. FLOW-3D software was employed to simulate the flow around a submerged spur dike. VOF method was used for free surface simulation and RNG k-ε model was used for turbulence modeling. Based on comparison of numerical and experimental results for stream wise velocity component and flow depth, it was concluded that numerical model could simulate the flow parameters with relatively high accuracy. In following, the effect of discharge increase on velocity profiles and flow free surface was investigated. According to obtained results, maximum longitudinal velocity Infront of the spur dike nose and flow depth at the upstream of spur dike increased with discharge increase. In lower discharges, the changes rate was more and vice versa. Also, the ratio of the flow depth at the upstream and the flow depth at the downstream increased with discharge increase.

Most rivers have bend routs that the quite complex flow pattern is dominated on them. It is necessary to study the behavior of a river, the flow pattern is well known that the dominant bend. Numerical models as a powerful instrument for the prediction of such areas can provide a good understanding of them. In the present study using three-dimensional numerical model Flow-3D, Parameters of U/Uc the flow pattern at a 90 degree arc of the moving bed is placed. The results were compared with experimental data.Analysis of results relevant to flow pattern in cross sections and different plans are among other points introduced in this paper.

Significant reduction in performance of watersheds in Iran due to the high volume erosion indicate the need for increased monitoring and follow-up of this destructive phenomenon. In this way، using new methods and knowledge is important. Around the world many erosion model as137Cs and RUSLE-3D model are used for soil erosion estimation. In this paper، soil erosion was estimated in Aghemam catchment by 137Cs and RUSLE-3D methods due to importance and high sensitivity of loess deposits in this area. Due to the lack of observed data in this area and because of high accuracy of 137Cs method in estimating soil erosion، performance of RUSLE-3D model was determined by Comparing data collected from 137Cs with RUSLE-3D model. The erosion rate was estimated 10. 78 ton/ha/yr by using 137Cs method، while this amount was 2. 61 ton/ha/yr by RUSLE-3D model. In this study the erosion rate obtained by two methods were compared in the slope classes of 0-15º and in > 15º، also in cultivated and uncultivated land uses. Finally these two methods have low correlation and RUSLE-3D model is not recommended in this area.

While the mass density current penetrates the stagnant fluid, a plunge point occurs. In this regard, the boundary of the dense fluid with ambient fluid is determined at the plunge point height. In this research, the hydraulic parameters of the dense flow and the bed slope of the stagnant fluid which have a significant effect on the plunge point have been investigated under the two turbulence models: the k- and the RNG at the Flow-3D model. To achieve the purpose of this research, a physical model was set up at the hydraulics laboratory of Shahid Chamran University (SCU), Ahwaz, Iran. Then, using the Flow-3D model with both the k- and the RNG turbulence model, the height of the plunge point was simulated according to the same experimental condition. Findings showed that the predicted depth under the RNG model is closer to the results of the physical model. For example, the k- and RNG model for the 12% slope can estimate the plunge point depth by 30% and 12.28% respectively more than the experimental data. However, for all the slopes, the k-e model can on average overestimate by 27% and RNG model 10.5% more than the results of experimental data. The statistical analysis showed that the RNG model predicts the plunge point depths with a satisfactory precision.

Three-side spillways are one type of dam outlets that despite of their hydraulic limitations and construction problems, under specific topographical conditions selected as one of the best options in storage dams. Considerable energy losses, great turbulence and hard stroking on bed and walls of lateral canal are some of undesirable hydraulic features of these spillways. Due to the complexities of fluid flow and the impact of scale, physical models do not provide a clear understanding of the physics governing the flow. In the complex flow and structures, is necessary to be considered, the laboratory studies, along with the numerical studies. In this study, Three-dimensional flow field in the three-side spillway and the end sill, have been investigated by using FLOW-3D software with finite volume method and RNG(k-e) turbulence model. Comparison of numerical results with experimental data showed that this model have a good ability to prediction three-dimensional flow pattern over this kind of spillways.

Using slot in bridge piers is one of the reduction methods of scour depth around them. In this study، the flow field around a cylindrical pier located in a smooth bed with and without slot was simulated using FLOW-3D software. The RNG k-ε turbulence model was used for closing the Navier-Stokes equations. The comparison of the numerical results and laboratory measurements for one bridge pier without slot showed that the model could predict velocity and shear stress parameters with reasonable accuracy. The influence of the slot width on the flow field around bridge pier was then investigated. The formed vortex at downstream of the pier became smaller by increasing slot width. In the largest slot case، this vortex was completely disappeared. Also، by increasing slot width، the value of the maximum velocity occurred adjacent the pier decreased، but its location was fairly constant. Finally، because of the lower reduction of the longitudinal velocity of the flow in the vicinity of the upstream face of the pier for the largest slot، shear stress pattern in this area was similar to that of the upstream area.

When the dense flow mass intersect to stagnant fluid, dense flow penetrates into statically fluid and plunge depth occurs. In this research, hydraulic parameters of density current and bed slope have been investigated, which these have a considering effect on plunge point. To achieve on purposes of this research a physical model in hydraulic laboratory of Shahid Chamran University was built and various experiments were performed. At all of the experiment, plunge depth was measured in the various discharges of density current, different of density 6, 9, 13 and 16 kg/m3 at three slope 8, 12 and 16 percent. Then using Flow-3D depth of plunge point for these experimental conditions was simulated. Findings show that depth of plunge point derived with Flow-3D is more than measured values as in 12% slope, mathematical model overestimate about 30%. While, for all of the slope bed, simulated results 27 percent is more than corresponding measured values. Statistical evaluation shows that ratio of measured valued to results of Flow-3D is about 0.8.

Increased use of drip irrigation systems in the country and farmer's tendency to use more efficient irrigation systems, has caused need to know about parameters and factors that affect irrigation efficiency. This Study was done to examine how water moves in the soil and soil moisturere distribution at Weather Station of Ferdowsi University of Mashhad. Inthisstudy, Hydrus 2D/3D Model performed by using data from laboratory and field analysis. Thes imulation results of soil moistureina 48 hour period were compared with the results offield measurements. The results showed that the model is very capable in simulating moisture contentin thesoil. Statisticalerroranalysiswas described to estimate model parameters using Maximumerror (ME), Root Mean Square Error (RMSE) and Mean Absolute Error (MAE). Based on the results of RMSE parameter in volume tricsoil moisture, forallintervals and all discharges RMSE was less than 10 percent that it shows that model hashigh ability in simulation. Maximum Error was up to 5% of and Mean Absolute Error was up to 2.05 % of volumetric moisture content.

Decreasing of fresh water resources and increasing competition for water by industrial, agricultural and urban users has been enlightening the needs for using of systems with the least water losses. Drip irrigation system has the least water losses as deep percolation and Evaporation. Dimension of wetting pattern is the most important factor to control deep percolation. Several models have been improved to predict the dimension of wetting patterns. In this study, the accuracy of several approaches used to estimate wetting zone dimensions was evaluated. This models including the numerical Hydrus 2D/3D model, the analytical WetUp software and two empirical models including Amin-Ekhmaj and Schwartzman -Zur. The average of RMSE for both directions was 8 percent for Hydrus 2D/3D, which showed that this model has very good accuracy. The ability of analytical WetUp software to estimate the depth and radius of wetting front was good and poor with 16 and 32 percent of RMSE respectively. Amin-Ekhmaj model has a good accuracy with 13.5 percent average RMSE and finally Schwartzman -Zur estimation of the wetting shape were not satisfactory.