Flow and Turbulence Measurements in a Diagonal Brush Fish Pass: A Field Study

This study aims to investigate flow and turbulence structure of a diagonal brush fish passage which has been constructed at the existing Small Hydropower Plant (SHP) on İyidere River on the East Black Sea Coast of Turkey. The flow and turbulence characteristics of diagonal brush fish pass were investigated in a 1.1 m wide rectangular flume with a bed slope of 10% for Reynolds and Froude number ranging between 3.45x104-2.4x105 and 0.15-0.16, respectively. By taking into account dynamic upstream water levels (H=101.20 m to H=102.05 m) of fish pass structure throughout the year, the vertical velocity profiles of different flow regions have been obtained by using Nivus instrument; whereas the turbulence quantities were gathered by measuring the three-dimensional instantaneous velocity fields using Micro acoustic Doppler velocimeter. The flow data were grouped for 4 different relative submergence of bristles. Thus, the analysis is done based on a physical basis and it will contain the most important hydraulic parameters of velocity field, turbulence, and flow depth for fish passage design. The main findings of this study can be summarized as follows: (i) a significant proportion of energy dissipation (\u3e50%) takes place in the brush plates with the vibration and bending of bristles, (ii) turbulent kinetic energy seems to be considerably lower for a same dissipated power in brush fish pass than other conventional fish passes (vertical slot and nature type), (iii) the turbulence intensities in the lateral velocity component were an important contributor to turbulence, and (iv) when the bristles are submerged the maximum turbulent kinetic energy value is tripled. The flow is quasi-uniform and in subcritical regime which provides different migration corridors with typical hydraulic conditions and, very important for the fish, these corridors continue through the complete fish pass. The results from this study would be useful to fish-pass designers

Turbulence measurements in the bubbly flow region of hydraulic jumps

A hydraulic jump is characterized by a highly turbulent flow with macro-scale vortices, some kinetic energy dissipation and a bubbly two-phase flow structure. New air-water flow measurements were performed in a large-size facility using two types of phase-detection intrusive probes: i.e. single-tip and double-tip conductivity probes. These were complemented by some measurements of free-surface fluctuations using ultrasonic displacement meters. The void fraction measurements showed the presence of an advective diffusion shear layer in which the void fractions profiles matched closely an analytical solution of the advective diffusion equation for air bubbles. The free-surface fluctuations measurements showed large turbulent fluctuations that reflected the dynamic, unsteady structure of the hydraulic jumps. The measurements of interfacial velocity and turbulence level distributions provided new information on the turbulent velocity field in the highly-aerated shear region. The velocity profiles tended to follow a wall jet flow pattern. The air-water turbulent integral time and length scales were deduced from some auto- and cross-correlation analyses based upon the method of Chanson [H. Chanson, Bubbly flow structure in hydraulic jump, Eur. J. Mech. B/Fluids 26 (3) (2007) 367-384], providing the turbulent scales of the eddy structures advecting the air bubbles in the developing shear layer. The length scale L. is an integral air-water turbulence length scale which characterized the transverse size of the large vortical structures advecting the air bubbles. The experimental data showed that the dimensionless integral turbulent length scale L-xz/d(1), was closely related to the inflow depth: i.e. L-xz/d(1) = 0.2-0.8, with L-xz increasing towards the free-surface. (C) 2008 Elsevier Inc. All rights reserved

Session B6: Hydraulic Design of an Innovative Baffle-Brush Type Fish Pass

Abstract: The flow characteristics (depth, velocity, energy dissipation) of a new baffle-brush type fish pass were investigated experimentally in a 2 m wide rectangular flume which has a bed slope of 4% for discharges ranging between100-550 L/s. In all experiments quasi-uniform and subcritical flow conditions, Froude number ranging between 0.17-0.23, were observed. The Darcy-Weisbach friction factor was negatively correlated with the relative submergence of the baffle. The turbulence intensities were ranged between %38-79 in the baffle zone and %13-31 in the brush zone. The hydraulic test results showed that this type of fish pass can produce adequate flow depth and favorable local flow velocities for the design discharge of 0.2 m2/s (relative submergence of brushes=1.03). The hydraulic test results reveal that baffle-brush fish pass fulfill the requirements of an efficient fish passage by providing tranquil flows and sufficient flow depths for different fish species. Consequently, the following design procedure can be used for the proposed baffle-brush fish pass: (i) required flow depth can be specified for the target fish species, (ii) the friction factor can be estimated based on the relative submergence of baffle, and (iii) for the given bed slope, average flow velocity and discharge values can be computed from Darcy-Weisbach formula. The main advantage of the proposed hydraulic design is that we can scale-up all the parts of this type in order to adjust it to almost any demand based on the model test results

Turbulent length-time scales distributions in hydraulic jumps

Air–water flow measurements were performed in hydraulic jump flows for a range of inflow Froude numbers. The experiments were conducted in a large-sized facility using phase-detection intrusive probes. The void fraction measurements showed the presence of an advective diffusion shear layer where the air concentration vertical distributions were successfully compared with an analytical solution of the advective diffusion equation for air bubbles. In the air–water shear layer, a new empirical relationship between the maximum air concentration decay as a function of both the distance from the jump toe and the inflow Froude number was derived. Air–water turbulent time and length scales were deduced from auto- and cross-correlation analyses based on the method of Chanson (2007). The result provided some characteristic transverse time and length scales of the eddy structures advecting the air bubbles in the developing shear layer. The turbulence time scale data showed an increase with the relative elevation above the bed, as well as some decrease with increasing distance from the toe. The dimensionless integral turbulent length scale Lxz/d1 was closely related to the inflow depth

Renewable energy policy in Turkey

Abstract: This study aims to explore the availability and potential of renewable energy sources in Turkey and discuss the government policies and economic aspects. Turkey is a country which has the highest hydropower and wind energy potential among European countries. Current energy policy of Turkey primarily aims to maximize geothermal, wind and hydropower potential of the country in next 15 years. In Several incentives were developed for electricity generation from renewable energy sources by the publication of Law No. 5346 in 2005. The most important ones are: ease of land acquisition and feed-in-tariffs which promises purchasing of electricity generated by legal entities with a price of 5-5.5 €c/kWh. Since Turkey is a European Union (EU) candidate its laws and regulations must be compatible with EU. As the legislation in EU member states is investigated it is apparent that Law No. 5346 should be restructured. This should include: (i) redetermination of feed-in-tariff amount according to type and capacity of renewable energy source, (ii) taking installed capacity into account instead of reservoir area for hydroelectric power plants as renewable energy source, (iii) making detailed Environmental Impact Assessment (EIA) report obligatory for renewable energy plants. The emphasis has been given on hydropower and wind energy. The renewable energy policy of Turkey has been compared with the advanced economies in Europe like Germany and Norwa

Nanofiber-enhanced lightweight composite textiles for acoustic applications

This paper proposes lightweight textile acoustic structure, wherein electrospun polyacrylonitrile-based nanofibers enhance sound absorption properties with no weight and thickness penalty. Polyacrylonitrile nanofibers with diameter of 110 ± 7 nm were electrospun on spacer-knitted fabrics by varying deposition amount and surface coating arrangement. Proposed novel approach eliminated additional processing steps such as handling and post-lamination and provided easy scalability of nanofibers at macro-scale. The results showed that the sound absorption of nano-enhanced specimens was improved drastically when deposited amount of nanofibers or its effective surface area increased. Sound propagation paths in different configurations were interpreted from sound absorption and air permeability measurements. The sound absorption coefficient values up to 0.7 are achieved in the low and medium frequency ranges with no weight and thickness penalty by tuning deposition amount and surface coating arrangement

G protein gene variants in schizophrenia

Various studies demonstrating enhanced vulnerability to apoptosis may contribute to the pathobiology of schizophrenia. Objective: Thus, G proteins may provide an intriguing link between the signal transduction, and apoptotic hypotheses of schizophrenia. In the light of these findings, we investigated whether G protein gene polymorphisms (GNAS1-T393C and GNB3-C825T) accounted for an increased risk of schizophrenia. Methods: The present analyses were based on 100 subjects diagnosed with schizophrenia, and on 100 unrelated healthy controls. The genotyping of GNAS1-T393C, and GNB3-C825T gene polymorphisms were performed using the polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP). Results: We demonstrated the positive association of GNB3-C825T gene variants with schizophrenia risk (p: 0.023). In our study, more prevalent CC genotype frequencies were detected in GNB3 in patients compared with the frequencies in the controls. The individuals with GNB3-C825T CC genotype had 2 fold increased risk for schizophrenia (p: 0.011, c2: 6.39, OR:2.14, 95% CI: 1.18-3.90). Discussion: Our study results suggested that GNB3-C825T polymorphism might be associated with schizophrenia

Dysplastic Ichthyosis Uteri-like changes of the entire endometrium associated with a squamous cell carcinoma of the uterine cervix

Ichthyosis uteri is an exceedingly rare condition in which the entire surface of the endometrium is replaced by stratified squamous epithelium. Originally described as an endometrial response to iatrogenically-introduced caustic substances, similar changes have since been described in association with a variety of inflammatory conditions of the endometrium. We describe herein a heretofore undescribed example of a moderately differentiated squamous cell carcinoma of the uterine cervix associated with extensive ichthyosis uteri-like changes of the entire adjacent endometrium. Additionally, the squamous epithelium of the latter also showed multifocal changes diagnostic of a low-grade squamous intraepithelial lesion. The potential genesis of this composite of findings is discussed, as is the neoplastic potential of ichthyosis uteri. It is concluded that a squamous cell carcinoma of the cervix extended proximally into the endometrium, and that there was a colonization of a pre-existing ichthyosis uteri by associated human papillomavirus. The possibility of significant cervical pathology should be considered when plaques of squamous epithelium with low grade dysplastic changes are identified in an endometrial biopsy or curettage