Identification of Underwater Vehicle Hydrodynamic Coefficients Using Model Tests (original) (raw)
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Hydraulic and Structural Analysis of Babolrud River Training Using Some Applied Software
DOAJ (DOAJ: Directory of Open Access Journals), 2019
Occurrence of heavy floods in rivers causes a lot of damages and losses. In this research, to highlight the river-training reaches in 10.9 km of Babolrud River, first, using topographic map of the area, the Tin layer was created in GIS software. Then, using the HEC-GeoRAS extension, the main route and cross sections of the river were prepared and introduced to the HEC-RAS model. River discharge with return periods of 2 to 200 years was calculated. Flow analysis in the agricultural and urban areas was performed and the areas which need training measures such as flood-retaining walls and levees were specified and designed. The structural design, stability control and sliding was performed based on the Standard No. 518, using RetainWall software, and design and control of levee stability was performed based on the Standard No. 214, using GeoStudio software. The cost of project implementation was estimated based on the Price List of 2017. The output of HEC-RAS software showed that height of flood-retaining wall in 3 urban reaches ranged between 1.73 to 2.8 m and in 5 agricultural reaches ranged between 1.46 to 2.25 m. It was concluded that the overall cost of levee implementation is about 9.01 billion Rials, of gravity concrete flood-retaining wall is about 9.26 billion Rials and of concrete cantilever inverted T shape flood-retaining wall is about 10.05 billion Rials. Thus, using floodretaining levee is the most economical option.
Background: Kinetic models in natural wastewater treatment systems design can have an important role to help designing other parts from aspects of physical, hydraulic and process in real scale, and to determine the strengths and weaknesses of system. So, the initial aim of wetlands design is removal of organic matter is, BOD 5 and COD, so. Determining the kinetic coefficients is necessary. Method: In the present study, reaction kinetics of biological removal of organic substances in wastewater in subsurface reed beds have been investigated. For this purpose, samples from three sites in the lagoon were taken monthly during 6 months and the removal of organic materials, sBOD5 and sCOD was calculated. Afterward, the results were analyzed using the first order kinetic models, second order, Stover -Keane canon and statistical parameters. Results: Results showed the average concentration output of sBOD5 and sCOD in control of wetlands and reed, were 101.49, 56.92 and 81.78 and 46.18 mg/L, respectively. In the predicted behavior of organic matter removal, Stover -Keane Canon model presented closest connection between theoretical predictions and data of field reed beds. And the maximum coefficient of organic matter (U Max ) in the wetlands with reed sBOD5 sCOD and control were 120.48, 142.85 and 33.3, 31.25 mg/L, respectively. Conclusion: According to the results, due to atmospheric conditions and design of Yazd wastewater treatment plant, the efficiency of this plant in removal of organic matter was high; Thereby provides sufficient reducing pollution and efficiency to meet the effluent outlet standards.
Stepped spillways have significant importance for their indisputable effect on energy dissipation and for compatibility with roller compact concrete method in construction. In order to design these spillways, physical models are commonly used in spite of spending great time and cost. Progress of high speed computers, however, permits to utilize computational fluid dynamic (CFD) method and therefore diminishing time and cost. In this research, some physical results are used for simulation of flow on stepped spillways, by applying FLUENT CFD package. Skimming and transitional regimes are investigated for the spillway. The simulated parameters were characteristic depth (y 90), characteristic velocity (V 90), clear water velocity and mean air concentration. Multiphase models consisting of volume of fluid (VOF), mixture and Eulerian and also turbulence models of k-ε, also coupling pressure-velocity algorithms of PISO and Simple were used both two and three dimensionally. Mixture and RNG k-ε for multiphase and turbulence models totally produced satisfactory results. The results were good for evaluation of the hydraulic parameters considering air bubble entrainment in skimming regime and relatively poor for transitional regime.
2019
Nowadays, simulation of viscoelastic flows at high Weissenberg numbers is one of the most obstacles and important issues for rheologists to observe the rheological properties at sufficiently high weissenberg number. It is well known that the conformation tensor should, in principle, remain symmetric positive definite (SPD) as it evolves in time. In fact, this property is crucial for the well-posedness of its evolution equation. In practice, this property is violated in many numerical simulations. Most likely, this is caused by the accumulation of spatial discretization errors that arise from numerical integration of the governing equations. In this research, we apply a mathematical transformation, the so-called hyperbolic tangent, on the conformation tensor to bound the eigenvalues and prevent the generation of negative spurious eigenvalues during simulations. The flow of FENE-P fluid through a 2D channel is selected as the test case. Discrete solutions are obtained by spectral/hp e...
The Water Productivity Assessment Approaching AHP, ANP, FAHP and FANP Methods (In Persian)
In this research, the Analytic Hierarchy Process (AHP) and Analytic Network Process (ANP) have been used in order to assess the four different water productivity indicators of an irrigation network in Iran. To compare these indicators, seven criteria have been chosen and the indicators were weighted in both AHP and ANP models using Super Decision 8.5 software. Using Delphi method and triangular fuzzy numbers, these models were transferred to Fuzzy AHP and Fuzzy ANP to distinguish and compare the pros and coins of AHP, ANP, FAHP and FANP. In an overall aspect, it can be said that AHP and ANP models are both applicable tools for multi criteria decision making. Since, AHP considers only the pair relationship between criteria and an alternative, its ability of decision making is weaker than ANP. Physical economical water productivity and Total factor productivity have been concluded to be the most suitable water productivity factors and yield, climate and water price were the most impor...
Determination of risk factors for lower extremity injury by video analysis during springboard diving
2019
Background: Competitive diving has both a high speed impact and chronic repetitive character. Jumping from the springboard with poor posture or the sheer volume of dives can increase risk of chronic overuse injuries. The purpose of this study was to evaluate the relationship between dynamic lower extremity malalignments and elite divers' approach the 1 m springboard. Methods: Passive or reflective markers were attached to posterior surface of the subjects' bodies. Twelve elite divers performed "Forward Diving Straight" with one of the Traditional (TRD) or Hurdle pre-flight (HPF) approach on the 1m springboard. Their dynamic malalignments of ankle, knee and hip were evaluated during diving performance. The relationship between approach pattern and dynamic malalignment of ankle, knee, and hip in the frontal plane at each step was determined using “Generalized Estimating Equation” (GEE) with the “Identity Function” and the “Normal Distribution”. Results: The results o...
ISFJ, 2017
Water reservoirs have an important role in providing water for drinking and agriculture. It is necessary to protect these resources. This study was conducted to determine water quality of Azad Reservoir (Kordestan-Sanandaj) based on Iranian Water Quality Index (IRWQI) and Carlson's Trophic State Index (TSI). Sampling was carried out at five stations during different months in 2015-2016. Results showed that trophic status of Azad dam was mesotrophic based on chlorophyll-a parameters and eutrophic to hypertrophic based on other variables (TP, SDD and DO % at bottom layers). Mean of Carlson's Trophic State Index represented mesotrophic state (high quality) at Azad dam. Based on IRWQI, water quality of dam was classified as excellent quality. Although, mean of indices indicated the suitability of this lake for drinking and agriculture activities but due to declining water quality and increasing trophic level in some months, it is necessary to apply appropriate management strategies for maintaining water quality in the reservoir.