Field and laboratory documentation of a building site exposure on western edge of Bělotín, Moravian Gate

A pebble sample collected near the critical sector of the Moravian Gate was analyzed. The clasts come from the upper part of the Lower Badenian marine sand and the pebbles scattered on the surface in the W environs of Belotin village (close to the European watershed between the Baltic and Black sea) where the overflow of the divide by the scandinavian ice sheet is still open to debate. The pebble petrology is a simple one, the clasts being composed mostly of sandstone and silicite with some quartz admixture. Most important for palaeogeographic interpretation are silicites, which might indicate nordic or local source. The microscopic study as well as RTG analyses proved a local provenance of opal silicites from the Menilitic formation (Carpathian Oligocene).A pebble sample collected near the critical sector of the Moravian Gate was analyzed. The clasts come from the upper part of the Lower Badenian marine sand and the pebbles scattered on the surface in the W environs of Belotin village (close to the European watershed between the Baltic and Black sea) where the overflow of the divide by the scandinavian ice sheet is still open to debate. The pebble petrology is a simple one, the clasts being composed mostly of sandstone and silicite with some quartz admixture. Most important for palaeogeographic interpretation are silicites, which might indicate nordic or local source. The microscopic study as well as RTG analyses proved a local provenance of opal silicites from the Menilitic formation (Carpathian Oligocene)

CFD simulation of dimpled sphere and its wind tunnel verification

Paper deals with problems of CFD simulating airflow over a dimpled spherical surface and its verification by the wind tunnel measurement. The low-cost simulation approach was applied to be run on a common PC using the commercial software ANSYS CFX. The wind tunnel testing has been performed in the laboratory of aerodynamics at the Department of Air Force and Aircraft Technology of the University of Defence. Measured results of the drag coefficient versus the Reynolds number for smooth and dimpled spheres were compared and discussed. Presented simulation corresponds adequately to the experimental results. It can be stated that the CFD simulation is suitable for simulating the flow over the dimpled surfaces similar to sphere

Performance analysis of a horizontal axis wind turbine

This paper presents a performance analysis of a horizontal axis wind turbine with an atypical design. The performance analysis was performed by a measurement in a low-speed wind tunnel. The atypical design of the horizontal axis wind turbine mimics the design of a radial turbine. The wind turbine was, however, simplified by “removing” the conventional stationary parts of the radial turbine, such as portion of the case or guide vanes. The paper describes the measurement test bed and compares the performance of this atypical wind turbine with more conventional designs

Performance analysis of a horizontal axis wind turbine

This paper presents a performance analysis of a horizontal axis wind turbine with an atypical design. The performance analysis was performed by a measurement in a low-speed wind tunnel. The atypical design of the horizontal axis wind turbine mimics the design of a radial turbine. The wind turbine was, however, simplified by “removing” the conventional stationary parts of the radial turbine, such as portion of the case or guide vanes. The paper describes the measurement test bed and compares the performance of this atypical wind turbine with more conventional designs

Pressure field in measurement section of wind tunnel

The University of Defence in Brno has a new low-speed wind tunnel. In order to confirm the quality of the wind inside of the measurement section, several measurements of the dynamic pressure have been performed with the Pitot-static tube. The pressure fields are then analysed and quality of the field is evaluated. Measurement of a pressure drop on the body of a standing helicopter was conducted

Pressure field in measurement section of wind tunnel

The University of Defence in Brno has a new low-speed wind tunnel. In order to confirm the quality of the wind inside of the measurement section, several measurements of the dynamic pressure have been performed with the Pitot-static tube. The pressure fields are then analysed and quality of the field is evaluated. Measurement of a pressure drop on the body of a standing helicopter was conducted

Experimental evaluation and set-up of a new apparatus designed for transitional flow experiments

Experimental exercise has been conducted to validate the capability of a new test apparatus. The test stand has been designed and constructed at the laboratory of aerodynamics, University of Defence to carry out the experimental investigation of transitional flow prediction and development over flat plate. The test facility consists of a rectangular duct set on the suction side of air source apparatus. The working section is 2 m long with a cross section of 0.44 m in width and 0.25 m in height. The exercise is performed into two stages. In the first stage, the basic parameters such as freestream velocity, turbulence intensity and pressure gradient in streamwise direction were measured and manipulated to setup acceptable values. Second stage of the exercise, the bottom wall of the test section was used as a flat plate model to conduct turbulent boundary-layer experiment. The characteristics of the boundary layer obtained by using the apparatus are represented by a qualitative and quantitative agreement with those predicted by boundary-layer theory for turbulent boundary layer while more improvements seems to be required to satisfy the rules of boundary layer stability experiments. The results are show a fair agreement for mean velocity profile, U∞, boundary layer thickness, δ, momentum thickness, θ, and skin friction coefficient, Cf

Determination of performance parameters of vertical axis wind turbines in wind tunnel

The paper deals with the determination of the performance parameters of a small vertical axis wind turbines (VAWT), which operate by the utilization of drag forces acting on the blades of the turbine. The performance was evaluated by investigating the electrical power output and torque moment of the wind machine. Measurements were performed on the full-scale model and the experimental data are assessed and compared to other types of wind turbines, with respect to its purpose

Experimental evaluation and set-up of a new apparatus designed for transitional flow experiments

Experimental exercise has been conducted to validate the capability of a new test apparatus. The test stand has been designed and constructed at the laboratory of aerodynamics, University of Defence to carry out the experimental investigation of transitional flow prediction and development over flat plate. The test facility consists of a rectangular duct set on the suction side of air source apparatus. The working section is 2 m long with a cross section of 0.44 m in width and 0.25 m in height. The exercise is performed into two stages. In the first stage, the basic parameters such as freestream velocity, turbulence intensity and pressure gradient in streamwise direction were measured and manipulated to setup acceptable values. Second stage of the exercise, the bottom wall of the test section was used as a flat plate model to conduct turbulent boundary-layer experiment. The characteristics of the boundary layer obtained by using the apparatus are represented by a qualitative and quantitative agreement with those predicted by boundary-layer theory for turbulent boundary layer while more improvements seems to be required to satisfy the rules of boundary layer stability experiments. The results are show a fair agreement for mean velocity profile, U∞, boundary layer thickness, δ, momentum thickness, θ, and skin friction coefficient, Cf

Determination of performance parameters of vertical axis wind turbines in wind tunnel

The paper deals with the determination of the performance parameters of a small vertical axis wind turbines (VAWT), which operate by the utilization of drag forces acting on the blades of the turbine. The performance was evaluated by investigating the electrical power output and torque moment of the wind machine. Measurements were performed on the full-scale model and the experimental data are assessed and compared to other types of wind turbines, with respect to its purpose