javad farhoudi

Data and information play a special role in the transparency of water governance. On the other hand, witnessing contradictions in water resources data and information, inconsistent readings and narratives about water assets, outdated hardware equipment, and to some extent software enhancement in the preparation and presentation of water resources information compared to global advances, necessitates a serious review of water resources data collection and processing systems. In this regard, artificial intelligence methods, sensors, and remote sensing technologies are considered in accurate water resources accounting. This article is a systematic review of about 100 international articles that present the latest findings related to software and hardware equipment for monitoring hydrological cycle meta-indicators. These meta-indicators include precipitation, water depth/water level/flow velocity and discharge of rivers, and groundwater level. In each case, while providing a list of the most important technologies, the application level of these technologies in monitoring surface and groundwater resources in Iran was evaluated. The conducted studies prove the unfavorable application technologies in monitoring hydrological cycle in Iran. For example, out of a total of twenty-six known technologies related to surface flow measurements, only two technologies have been widely used Iran; four technologies have reached the knowledge frontier and widespread production by domestic knowledge-based companies, and eleven technologies have not yet reached the knowledge frontier Iran. In this paper, suggestions were presented to outline the path for developing new technologies for water cycle data collection and transformation in the modernization of Iran's water resources data collection and data processing infrastructure.

Examining the changes in the water quality parameters of the Karun River using satellite data and determining the modified quality indicators can be used to assess the vulnerability of irrigation water. In this research, the data of seven qualitative parameters: Na+, SAR, pH, Cl-, HCO3-, EC and TDS were used in six water measuring stations of Abbaspur, Ahvaz, Farsiat, Gotvand, Molasani and Soosan of the Karun River (1392-1398) and NSFWQI general water quality index was calculated. Correlation relationship and estimation errors were determined for two principal component reduction (PCA) and multivariate linear correlation methods. The results showed that multivariate correlation method is more suitable. The coefficient of determination for the seven water quality parameters was calculated as 0.44, 0.43, 0.03, 0.43, 0.09, 0.45 and 0.46 respectively, and for the NSFWQI index it was calculated as 0.46. The statistical correlation for pH and HCO3- is at a very low level; but for the other five parameters and the NSFWQI index, it is in average state. The significance level of estimation for Na+, SAR, Cl-, HCO3-, EC and TDS parameters is acceptable (P<0.001), and for pH is unacceptable (P<0.122). In general, there is an acceptable correlation between the bands extracted through the Landsat 8 satellite and most of the quality parameters of the Karun River, but necessary actions are proposed to improve the correlation relationships. Also, the NSFWQI index shows that the quality of water in the Karun River along the Khuzestan plain is not good enough.

Dam removal is one of the methods of restoring the river ecosystem. The decision to remove a dam is based on the multidisciplinary indicators and the type of dam body and its location, as well as the downstream conditions and the type of dam removal method. In the present study, the removal of the Voshmgir Dam on the Gorganrud River, Iran, was considered, because of the high volume of sediment deposition in the reservoir and the loss of its useful life. Three scenarios were selected for the removal of the dam: 1- complete removal; 2- stepped removal of the spillway; and 3- removal with stable sediments. In the first step, numerical modeling for river morphological changes was performed using the HEC-RAS model for unsteady flows with sediment transport. The erosion and sedimentation processes were simulated in six reaches (from the Voshmgir Dam to the Caspian Sea), with total length of 128 km. The results indicated that the second scenario (stepped removal of the spillway) is the best alternative due to the gradual processes of river-bed changes. In the present research, the two-dimensional hydrodynamic and water quality model CE-QUAL-W2 is used for qualitative modeling of Gorganrud River in three scenarios of dam removal, within 128 km downstream of Vashmgir dam to the Caspian Sea Estuary. Qualitative modeling was performed for the existing conditions of Gorganrud (without removing the Vashmgir dam) at two hydrometric stations of Aqqala (68 km downstream of the Vashmgir dam) and and Basirabad (112 km downstream of Vashmgir Dam), where a set of water level and water-quality data was available for model calibration. Model results are presented in the period of rapid river changes after dam removal up to 60 days. Based on the results of qualitative modeling, the amount of dissolved oxygen (DO) has increased in three scenarios of dam removal in two sections of the river (Aqqala and Basirabad). The amount of biochemical oxygen demand (BOD) in the first scenario (complete removal) and the second (stepping removal) has increased slightly (less than 10% of the river conditions before removal). In the third scenario (removal with stable deposition), no significant change in BOD occurred. In three scenarios and in both study periods, the pH changed very little in the two periods, before and after the removal of the dam. The total amount of soluble solids (TDS) in the early days of the simulation is equal to or greater than that before removal. The TDS rate is to be decreased by time. The overall results indicated that the second scenario of the dam removal (i.e. stepped removal of the spillway) is the best alternative due to the less impacts on the river-bed changes, and the gradual processes of river-ecosystem rehabilitation.

Sustainable river management requires the construction and operation of dams that provide environmental flows to support downstream rivers ecosystem. Dam construction in Iran has significantly altered natural flow regimes and caused various environmental issues. The main aim of the present study was to evaluate the hydrologic and environmental alteration of the flow regime in the Jajrud River downstream of the Latian Dam. In this study, a set of long-term flow data (1947-2017) was analyze using the IHA and RVA models. The results show that the degree of alterations for the 24 flow variables is in the range of high to medium, denoting the high hydrological alterations of the Jajrud River. The values of mean, maximum and minimum monthly flows have decreased by 57, 94 and 21 percent, respectively. The overall change is 51%. Magnitude and duration of annual extreme flows have decreased, and in particular, the minimum flows and the base-flow indices have changed the most. The large flood events has been eliminated and small and frequent floods has been damped in the downstream river system. The results indicate that the goals of RVA have not been achieved in the post-construction period of the Latian Dam, and the environmental conditions of the river have been severely damaged. With reference to the eco-hydrological indices, the rehabilitation of the environment status of the Jajrud River requires the dam releases of minimum monthly flows in order of 2.3 to 33.8 m3/s, with an average annual discharge of 6.5 m3/s.

Dam removal is one of the methods of restoring the river ecosystem. In the present study, the removal of the Voshmgir Dam on the Gorganrud River, Iran, was considered, because of the high volume of sediment deposition in the reservoir and the loss of its useful life. Three scenarios were selected for the removal of the dam: 1- complete removal; 2- stepped removal of the spillway; and 3- removal with stable sediments. Numerical modeling for river morphological changes was performed using HEC-RAS model for unsteady flows with sediment transport. The erosion and sedimentation processes were simulated in six reaches (from the Voshmgir Dam to the Caspian Sea), with total length of 128 km. The results indicated that the first scenario causes the highest rate of both erosion and sedimentation in the river reaches. In the second scenario, the intensity of river-bed changes is considerably reduced, and the highest deposition and erosion occurs in the first and the fifth reaches, respectively. The simulation results from the third scenario were uncertain. The second scenario (stepped removal of the spillway) is recommended due to the less impacts on the river-bed changes, and gradual processes of river-ecosystem rehabilitation

One of the structures for controlling and measuring flow in open channels are the sluice gates. In this study, to estimate the outflow from the sluice gates, the existing relationships for orifices evaluated theoretically and experimentally. A new method was established for estimating the contraction coefficient and energy loss coefficient under free-flow condition. Some equations proposed to estimate the outflow from sluice gates under submerged flow conditions using the energy-moment principles and relationships for orifices. In order to evaluate the accuracy of recommended relationships, the outflow from the sluice gates was experimentally tested in a channel of 18 meters long and one meter wide. Comparison of the results showed that all the presented orifice relationships have similarly good capabilities to estimate the outflow from the sluice gates under free-flow conditions. It was concluded that the applying of Henry relationship would be the simplest one in determining the contraction coefficient. Under submerged flow conditions, all the orifice relationships have competent accuracy in estimating the flow rate, with an order of errors less than 10 percent. Under full ranges of free to submerged flow conditions, the discharge coefficient can be determined by the relationship of Rajaratnam and Subramanya as a function of the head loss coefficient, the contraction coefficient and the opening-to-depth ratio.

In practical applications, for instance, at the downstream of hydraulic structures, in some cases the width of the basin may be larger than the upstream supercritical flow (sudden expansion in flow section). In such cases, an expanding hydraulic jump with symmetrical or asymmetrical shape will be developed at the downstream. Under the design of three parallel gates, the operation of the side or middle gate can be lead to the asymmetrical or symmetrical hydraulic jump, respectively. According to the position of jump toe, expanding hydraulic jump can be classified into four types. The present study focuses on a T-shaped hydraulic jump which the toe is established at the beginning of the divergence section.Most of the previous studies are related to the symmetrical expanding hydraulic jump. In this case, the downstream diverging channel is symmetric on the central axis of the channel. However, a systematic study investigating the effect of symmetry and asymmetry on the expanding hydraulic jump was not found in the literature. In this study, using the momentum principle, some theoretical equations were derived to determine the sequent depths ratio of symmetrical and asymmetrical expanding hydraulic jump. Also, some regression relations were proposed to estimate the length of expanding hydraulic jump. The new proposed equations were also extended for the presence of a sill. The equations were calibrated using available experimental data from this study and the literature. This research also considered the characteristics of expanding hydraulic jump under the symmetrical and asymmetrical operation of parallel gates.

To calibrate the new proposed relations and investigate the effects of different parameters on the expanding hydraulic jump characteristics, two experimental data sets were used. In addition to the data set from Bremen (1990), the experimental data from the present study were used. The data were collected from a hydraulic model of three parallel radial gates for operating the side or middle gate which corresponds with the asymmetrical or symmetrical expanding hydraulic jump, respectively. The experiments provided a wide range of different parameters as the approaching Froude number, hydraulic jump length, sequent depths ratio, divergence ratio, sill height and relative length of gate separator wall.

Equation (4) was developed to determine the ratio of the sequent depths of expanding hydraulic jump based on the Momentum equation. For the presence of a sill, a combination of Equations (4), (7) and (8) can be used to calculate the ratio of sequent depths under the asymmetric and symmetric developments, respectively.Determining the ratio of the sequent depths requires the calculation of the adjacent water depths of the closed gates. For this purpose, in addition to developing the regression equation (Equation 13), Equation (12) was proposed which based on the calculation of the hydraulic jump profile. It was observed that under the calibration range, the regression equation is more accurate. However, Equation (12) is recommended for the range outside of the experimental observations. The results showed that:As the divergence ratio increases, the ratio of sequent depths approaches to the classic hydraulic jump.By decreasing the relative length of the gate separator wall and decreasing the width of the gate on the downstream channel width, the relative depth at the side gate and consequently the ratio of the sequent depths will decrease.For the lower length of separator wall and under operation of the middle gate, more lengths are needed to develop the jump than the side gate. However, as the length of the separator wall increases, the length and sequent depth of hydraulic jump due to the side gate increases on the middle gate.In the presence of a sill, the relative length of hydraulic jump decreases and the ratio of secondary depths increases.It was observed that the hydraulic jump due to the operation of the middle gate leans toward the left or right side of the channel due to oscillatory behavior.Under operating the middle gate and in the absence of a sill, an asymmetric hydraulic jump is formed in the channel face when the length of the separator wall is less than 38% of the classical hydraulic jump length. For the presence of a sill, the minimum length of the separator wall decreases to about 26%.By decreasing the initial depth of the hydraulic jump on the width of the gate and converting the output jet into a linear jet, the relative development length will increase.
As the sill height increases, the difference in the depths attached to the side gates will decrease and the hydraulic jump will develop more symmetrically.As the relative height of the sill decreases, the minimum length of the separator wall to form a symmetrical hydraulic jump in the flanks, increases.

This research developed a set of theoretical and regression relationships for estimating the length and sequent depth ratio of expanding hydraulic jump. Moreover, the effects of sill height, divergence ratio and the length of the gate separator wall, were investigated. This study compares the effects of side and middle gate operations based on the variation of jump length and sequent depth ratio. The results can be used as a guide for the hydraulic structures operators to reduce the asymmetric severity of the expanding hydraulic jump and achieve the complete development under the minimum length.

One of the most commonly used devices for flow measurements in open channels is the flume, in which the flow velocity increases due to the lateral contraction, raising the bottom of the channel, or a combination of both them. SMBF is a flume with the above mentioned properties, having two semi-cylinders on the side walls of the channel that contract the cross-sectional area of the flow. In this study, the SMBF flume has been studied for measuring the flow in free and submerged flow conditions. Using the experimental data (575 runs) of two rectangular channels, and using eight SMBF flumes, the proposed discharge equations were examined for the wide ranges of flow discharge, upstream depth, and contraction ratio. In the present study, based on the numerical and experimental analysis, and by measuring the velocity distribution at the throat section, non-uniformity of velocity distribution and depth in the contracted section, as well as the two-dimensional nature of flow were studied. Then, by considering the flow correction coefficients in the throat section and applying them into the energy equation, an equation was developed for estimating the flow discharge‎ under free flow conditions. Also, two equations were developed to determine the submergence threshold (as a function of upstream depth and throat width) and for the discharge estimation under submerged conditions. The mean absolute relative error of the estimated flow discharge of the SMBF flumes in free flow conditions and based on three experimental data series (channel 1, channel 2, and other researcher’s data) were respectively estimated to be 2.82, 3.19 and 1.52%. Additionally, the mean absolute relative error of the estimating flow discharge in the submerged conditions was 5.51%. The results showed a feasible application of SMBF structure, as a portable measuring instrument under free and submerged conditions.

Since there are a few reports available regarding the hydraulics of flap gates, it was aimed to conduct a research work on these kind of structures to make it clear whether they could be meet the desired advantages in flow measurement activities. Flap gates are made of cast iron or ductile iron, depending on the type of service. A small differential pressure on the back of the gate causes it to open automatically to allow discharge through levees, sewer lines or drainage conduits. When level of water on the face side of the gate rises above water level on the back side, the gate closes automatically to prevent backflow. Automatic drainage gates must be kept clean if they are to function correctly. The hinged flap acts as a natural skimmer to cause timber, logs or trash to catch between the flap and the seat at low flow. Periodic inspection and cleaning should be scheduled when the water flowing through the flap gate carries floating material. Flap gates provide a simple and cost-effective mechanism to maintain upstream water levels and flow measurement in small canals. Once installed and proper operation is verified, the gate only requires lubrication of its bearings and occasional painting for maintenance. It needs no electric power and no manual adjustment for varying flow rates. This gate can be used in open channels with rectangular section or circular section and ducts under pressure, for flood control, municipal projects, farm levees, sewer outfalls, industrial waste lines, water and sewage treatment plants, tidal drainage, irrigation systems and pump discharge control. In recent years, huge developments have been achieved on flow measurement. However, these achievements were faced with high installation and operational costs as well as highly trained human sources for their better utilization. Therefore, revision in traditional flow measuring tools is needed to get an acceptable precision and low cost of erection and operation. Present research covers the results of a theoretical and experimental investigation on a circular and quadratic flap gates which installed at the exit of a circular channel. Two individual circular pipes of zero slope and diameters of 200 mm and 300 mm were selected as water reach. All experiments were conducted in a circular plexiglas-walled fume, 5.7 m long, having a recirculation flow system. To measure the flow discharge, a sharp triangular weir with apex angle of 90˚ in the upstream of channel and the conveyor to measure the gate opening was used. In this study, the flap gate was tested with different weights. For circular Flap Gate Dimensionless weight (w/ (ρgD3)) varies from 0.0343 to 0.2542 and for square flap gates these values vary from 0.0562 to 0.3305. During tests dimensionless discharge for circular flap gate varies from 0.0123 to 0.2503 and for square flap gates these values vary from 0.010 to 0.258, As well as the circular gate opening which was in the range of 0.0123 to 0.4088 (radian)and for square flap gates these values were in the range of 0.0174 to 0.4012 (radian). The relevant theoretical equations were established to determine the flow discharge and then calibrated by using of experimental observations The research took the advantages of tentative method, basic equation of weir discharge and momentum principles. The values of maximum error (ME), mean absolute relative error (MARE) and root mean square error (RMSE) were computed and used for comparison. The resulting equations of different methods were calibrated and verified by using about 98 laboratory data for circular flap gate and 97 laboratory data for quadratic flap gate. In, basic equation of weir discharge mean absolute relative error for circular flap gate is equal to 4.41% and 5.55% for quadratic flap gate, this amount is in order for momentum principles 5.66% and 6.84%. A comparison of the values from the derived equation with statistical criteria demonstrated a high accuracy basic equation of weir discharge. It was shown that the proposed method would demonstrate high accuracy in estimating the flow discharge of the flap gates under free flow regime. The absolute relative error was ranging from 3.34 to 6.66 for circular gate, and 4.1 to 8.14 for quadratic flap gate. Advantage of theoretical equation in comparison regression equation is it can be used outside of experimental data but regression equation just has interpolation capability.

Most of the previous studies related to radial gates are focused on the estimation of discharge from the gates as a flow measurement structure. However, determination of the gate opening for passing a certain value of the discharge is rarely considered in previous studies as a regulator structure. The present work presents some theoretical equations for explicit estimation of the outflow from the gate (first problem), and gate opening (second problem) for free and submerged flow conditions by combination of Energy and Momentum principles. For any problems, it was developed some criteria to identify flow conditions These equations were calibrated and validated by means of 2657 experimental records retrieved from research conducted on three types of radial gates. The paper would present an analytical approach to illustrate the reliability of proposed equations for estimation of discharge and the opening of the gate by taking benefits from the mean absolute relative errors which observed to be 1.94% and 2.67, respectively. It was noted that the used criteria conform with 99.6% and 98.8% of all observations at first and second problems, respectively. The results show that the tailwater depth under distinguishing limiting decreases by increasing in the gate lip angle and the ratio of turnnion pin height to the gate arm radius. Also, the hard rubber bar gate tends to operate under free flow condition in a wider range in comparison with two other gates.

Flap gates are used to measure the flow in canal and are considered as a hydraulic engineering topic, which lacks enough attention so far. Use of flap gate as a measuring tool requires extended studies in order to be recommends as a measuring device for different types of gates. The structures could provide an acceptable economic condition in flow measurement applications where, low costs of manufacturing, installation, and operation could be achieved. This paper presents the discharge estimation from flap gates in rectangular canals under free and submerged flow conditions by using regression and analytical techniques. The derived discharge equations are resulted from the combination of energy and momentum equations. The suggested equations were validated by means of experimental observations, which showed an average error of 1.06% to 1.91% at free flow and 2.28% to 5.26% for submerged flow conditions. The paper also presents some diagrams for estimating the discharge coefficient of flap gates in both flow conditions.

Present research covers the results of a theoretical and experimental investigation on a circular and quadratic flap gate, which installed at the exit of a circular channel. This study would employ an experimental program in a horizontal channel of circular cross section of 200 and 300 mm diameters, equipped with either a circular or quadratic flap gate to explore the basic parameters affecting the flow discharge estimation of these devices. In this study, of three ways such of the first form Stage-Discharge technique, incomplete self-similarity theory and the second form Stage-Discharge technique have been used for estimating the discharge for circular and quadratic flap gate under free flow conditions. The research took the advantages the main difficulties during the experiments were the vibration of the gate as well as accurate measurement of gate opening. The use of second form Stage-Discharge technique would overcome such weaknesses. The most accurate of these methods is incomplete self-similarity theory. In this theory, mean absolute relative error for circular flap gate is equal to 3.34% and for 4.1% for quadratic flap gate.

Local scour downstream of hydraulic structures is one of the critical phenomena, which has absorbed a vast amount of interests by researchers. The designers of hydraulic structures, particularly, spillways try to utilize proper means to minimize the consequences of excess energies downstream of such structures which usually tend to erode their immediate downstream reaches. The stepped spillway is designed to create a large amount of energy losses by action of its steps to lessen the amount of scour evolution at its immediate downstream. This article presents the results of 67 experiments conducted at two different scales of stepped spillways, to study the local scour downstream of the structure. The experiments were planned to consider a wide range of geometrical factors, flow characteristics, and sediment properties. The time duration of experiments was ranged from 6 to 24 h which produced more than 80000 data points for analytical considerations. The results were used to render some regression equations to define the similarity among the scour hole profile and its geometrical characteristics. It was observed that a long-term observation would be required to reach the equilibrium state. However, semi-equilibrium conditions will be achieved some times after 24 h. It was also noted that the depth of scour hole adjacent to channel walls was bigger than that of centerline. Finally, it was realized that the stepped spillway causes energy dissipation between 42.06 and 74.82% which results in a shallower scour hole compared to ogee spillways.

In recent years, considerable accomplishments were devoted for developing non-hydrostatic models for simulation of water level in open channel flows. The main constraint to develop such models, arises from true definitions of water surface boundary condition. Some costly techniques such as VOF and MAC are used for these purposes. These techniques are confronted with high computational costs as well as durability limitations beside their apt accuracy. Another group of non-hydrostatic models determines the water surface elevation using kinematic equation of free surface. These models are of suitable efficiencies if the water level gradient is negligible. Generally, in such conditions, equal number of cells in column and varied height of cells in surface layer are considered. If water level gradient is high, a considerable parts of flow field are solved in hydrostatic condition which frequently occurs in water level of groundwater.
To overcome these limitations in this research, the number of cells in each column was selected proportionate to varied water level which resulted in considerable improvements of water level and flow field. In fact, this technique falls in between VOF and the kinematic boundary condition of water level calculations. It was observed that the accuracy of this method is higher than the kinematic boundary condition with a lesser computational works and stability limitation than VOF. It is noteworthy to mention that, in wave interaction with porous structure test, with time step 6 times greater than VOF model, the current scheme is stable and considering running time, 480 percent more efficient.
The number of cells in each time increments was adjusted commensurate with water level.
This article details a vertical two dimensional non-hydrostatic model for simultaneous simulation of open flow level and water level in porous media. The governing equations are the developed forms of Navier-Stocks equations which commonly applied to fluid and porous media. These equations were discredited by means of finite volume method in Cartesian coordinates and solved by means of pressure bearing approach. The developed model is capable of solving the pressure field taking the advantages of the kinematic free water level and developed form of Navier-Stocks equations. The standard model of was used to model the turbulence.

Hydraulic jump on adverse stilling basin is an unstable phenomenon which causes some complexities in controlling of the jump. This paper considers the stability of free hydraulic jump on adverse stilling basins from a theoretical point of view. A minimum value of upstream Froude number is needed to produce the free hydraulic jump on adverse stilling basins which was presented by a theoretical equation. Also, the effects of an end sill and divergence in section on the minimum Froude number were investigated. Moreover, it is required that the bed has a minimum friction for making the jump stable which is obtained as a function of upstream Froude number and bed slope. This condition was compared with the criterion proposed by previous researchers and showed the considerable deviations at larger bed slopes. The result showed that it is impossible to establish the hydraulic jump on concrete adverse stilling basins without any appurtenances. However, diverging in section can improve the stability of hydraulic jump on adverse stilling basins.

Because of the complexity of the physical processes in the vicinity of the hydraulic structures due to the separation of the flow, traditional methods for for prediction of maximum scour depth downstream of hydraulic structures are mostly based on empirical approaches. Hence, only a few theoretical works have been reported to study this phenomenon. The present paper describes a new approach based on the momentum principles to estimate the maximum local scour depth downstream of a submerged sluice gate flowing over horizontal or adverse stilling basin. A control volume of the fluid in the equilibrium state of the scour hole was considered and based on momentum principles, some equations are derived to estimate the scour depth at equilibrium state. To verify the proposed equations, large numbers of experiments were planned and conducted under wide range of characteristic parameters such as, incoming Froude number, sediment size, tailwater depth, length and slope of the apron. It was found that the proposed equations fall in a good agreement with experimental results. It was also observed that, in the case of horizontal apron, a specific tailwater depth exists with which the local scour depth attains a minimum value. However, in the case of adverse basins when the tailwater depth takes a specific value, the maximum depth of the scour hole reaches to its maximum and then decreases to a constant value as the tailwater depth increases. This critical tailwater depth was formulated using a semi-theoretical equation.

In this paper a numerical investigation is given for a Rankine type vortex flow inside the cylindrical vortex chamber using FLOW-3D. The FLOW-3D is a general purpose computational fluid dynamics (CFD) package. The fluid motion is described with non-linear, transient, second-order differential equations. Additionally the free surface also exists in many simulations carried out with FLOW-3D because flow parameters and materials properties, such as density, velocity and pressure experience a discontinuity at it. After analysis of the vortex by mentioned details, the finding of time-averaged velocity components, turbulent components, turbulence dissipation, in the 2D briefed sections of chamber were depicted. It was found that there are different flow patterns like clockwise/anticlockwise vortices and some sink points combined with each other in different time intervals, decaying and generating along the time. Also the turbulence intensity and dissipations around the boundary conditions of chamber like central flushing discharge are higher than the flow body. It was also found that this CFD package was not able to simulate thoroughly the central air core of chamber after filling of chamber. This analysis is validated by comparison with previous experimental data that was measured in vortex settling basin.