Introduction: Side weirs are important and practical hydraulic structures in water conveyance systems that are installed on the side wall of the channel to divert excess water from main channels. In this research, the effect of the height of two-side semicircular labyrinth side weir on the discharge coefficient and water surface profile in 3D by using the FLUENT software. Methods: In this research, side weirs were used in three, four and five cycles with a height of 10, 15 and 20 cm and an opening length of 40 cm. The discharge coefficient and water surface profile obtained from this simulation were compared with experimental results for validation. Findings: The results showed the computed values have a good agreement with the experimental data and the error percentage for the discharge coefficient is between zero and 7% and the relative error was decreased by decreasing of Froude number. Based on the results, as the height of the side weir increases, the rate of water surface fluctuations in the main channel and along the side weir decreases. On average, with every 5 cm reduction in the height of the side weir, the rate of water surface decreases by 3%. Also, the discharge coefficient of the side weir decreases with decreasing congress radius and with increasing the side weir height and upstream Froude number. Therefore, the semicircular labyrinth side weir of three-cycle with height P = 10cm has a higher discharge coefficient than the other side weirs under study Conclusion: Investigation of the effect of semicircular corrugated side weir height on discharge coefficient and water surface profile, made it possible to investigate discharge coefficient and water surface profile in different models by changing the side weir height, radius and number of labyrinth cycles, with the shortest time and without the cost of overflow construction.

Discharge coefficient of a semicircular labyrinth weir is a function of total head, effective length of crest and discharge coefficent. Discharge coefficient of such a weir is influenced by total head over the weir, height of weir, radius of weir, thickness of weir and shape of crest. In this paper the effect of imporant parameters affecting discharge coefficient are investigated. It was found that by increasing the radio us of weir, discharge coefficient increases. The rate of variations of discharge coefficient decreases by increasing depth of flow and finally maintain a constant value.Appropriate equations for discharge coefficient are introduced. New method of design is introduced.

Heat transfer characteristics of supercritical CO2 in horizontal semicircular channels are numerically investigated using Computational Fluid Dynamics method validated with experimental data. Comparison study is conducted for semicircular and circular channels with the same hydraulic diameter and boundary condition at the bulk temperature range including pseudocritical point. The results show that the heat transfer coefficients of the semicircular channel are significantly smaller than those of the circular channels due to the blocking effect at the corner area of the channel cross section, and the fluid thermophysical properties near the wall have a significant effect on the convective heat transfer performance in both heating and cooling cases. A modified model was proposed based on Olson correlation of the semicircular channel considering the channel geometry and near-wall fluid viscosity influence. Further study was conducted to discuss the effect of hydraulic diameter and boundary conditions on the heat transfer performance of the semicircular channel and indicate that the modified correlation shows a reasonable prediction of the heat transfer coefficients in the heated semicircular channel.

The Present study introduces the slit and solid semicircular flap plates for flow measurement in horizontal open circular canals under free flow conditions. This structure consists of a semicircular plate which is installed and hinged from its diameter along a circular canal. The deviation generated by the water flow on the plate is a function of hydraulic characteristics of flow, the geometry of the structure and flow discharge. This simple measuring structure is portable and can easily be installed in circular canals and be used with acceptable precision. In this study, based on the theoretical and experimental studies of the passing flow through the semicircular flap plate, some equations were developed for estimating the flow in circular canals via the dimensionless discharge-critical depth relation. In order to calibrate the proposed equations, the laboratory data were collected and used. In addition, to estimate the passing flow through the flap plate, an explicit relationship was developed to compute the dimensionless critical depth and discharge. The dimensionless critical depthdischarge method used in this study is able to estimate the flow discharge through the semicircular plates with an average error of 3%. Due to the low average errors of the proposed discharge equations for the semicircular flap plate (an average error of 3. 6% without considering the Reynolds number and an average error of 3% by considering the Reynolds number), this structure is suggested as a discharge measuring structure in circular open canals.

In this article, an attempt has been made to estimate the amount of sound transmission loss in a flat oval channel by applying the approach of statistical energy analysis. Correct estimation of sound transmission loss in an air conditioning channel is of great importance due to the harmful effects of noise pollution in the environment on human health. Simulation with the statistical energy analysis method is a powerful approach to estimate sound and vibration in problems in which we deal with complex and multi-part systems; is considered. In this method, first, a system is divided into several subsystems, and then by writing a matrix equation that includes the energy exchanges between subsystems and energy loss coefficients; It is investigated from the perspective of vibration and sound estimation.On average, the model presented in this research is able to estimate the sound transmission loss in different dimensions of the air conditioning channels according to the experimental results in the accuracy range of ± 2.5 dB. Considering that it seems that the results obtained from modeling with this method are in good agreement with the experimental data; The results of this research can be used as an efficient approach to estimate noise in oval shaped channels stretched in different lengths.

Background and Aim: Behcet’, s disease (BD) is a multisystemic, chronic and progressive disorder with a relatively high prevalence in Iran. Therefore, this study aimed to compare the vestibular function between Iranian BD patients and normal subjects using cervical vestibularevoked myogenic potentials (cVEMPs) and video head impulse test (vHIT). Methods: In this cross-sectional study, 44 patients with definitive BD in the inactive stage of disease and 30 age and sex matched normal subjects were evaluated via cVEMP and vHIT tests and dizziness handicap inventory (DHI). Then the parameters of the tests were compared between the two groups by statistical methods. Moreover, the effects of DHI scores and other contextual variables on the test results were examined. Results: In terms of the cVEMP test, the response rate and mean latency of p13 in the left ear were significantly lower, the amplitude of the cVEMP wave in the left ear and the amplitude asymmetry ratio were significantly higher in BD patients compared to normal subjects (p<0. 05). Fifteen BD patients had abnormal amplitude and nine patients had abnormal latency of cVEMP responses. In terms of the vHIT test, the mean vestibule-ocular reflex gain of the left posterior semicircular canal and the mean gain asymmetry ratio of lateral canals were significantly higher in BD patients than in the controls (p<0. 05). Conclusion: the vestibular system of some patients with BD is disturbed and the results of this study indicate the presence of unilateral vestibular weakness in BD. So vestibular assessment can be helpful for these patients.

Tubular channel angular pressing (TCAP) is a recently invented severe plastic deformation technique for producing UFG tubes.Plastic deformation analysis using the finite element method (FEM) was carried out to investigate the effects of trapezoidal channel geometry on strain inhomogeneity index (SII), strain level and required load compared to the previously-used channel geometries. The results showed that SII decreases to 0.003 in the case of trapezoidal channel while it is 0.13 and 0.24 in the cases of semicircular and triangular channel types, respectively. It means that excellent strain homogeneity is achieved in TCAP processing using trapezoidal channel geometry. The required load for the trapezoidal channel was 41% lower than that for the triangular channel but it is almost the same for semicircular channel. From the point of view of better strain homogeneity and requiring lower process load, TCAP processing using trapezoidal channel is an excellent technique for producing UFG tubes.

Weirs are one of the widely used hydraulic structures for measuring discharge in open channels. This study applies two artificial intelligence models named artificial neural network (ANN) and genetic programming (GP) to predict discharge flowing over semicircular weirs with different openings including sharp and semicircular crests. The considered data base was selected from the literature. The results of AI models were compared with those of two empirical formulas, which have been developed based on the same data for this purpose. Four evaluation criteria were considered for comparing the estimated discharges. The results obviously indicate that GP outperforms others based on the considered criteria.