Vid konstruktion av flygplan uppkommer svårigheter att efterlikna de tänktadriftsförhållandena vid vindtunnelprovning av mindre skalmodeller. Dessa svårigheter berorfrämst på att ekonomiska och skalbara begränsningar gör att tillräckligt stora vindtunnlar intekan byggas för att generera de strömningshastigheter som ger samma Reynoldstal som för detänkta driftsförhållandena. För att komma runt detta problem kan så kallade störelementanvändas vilka inducerar en övergång mellan laminär och turbulent strömning i skalmodellensgränsskikt och möjliggör vindtunnelprovning i lägre strömningshastigheter. Detta arbete ämnardärför att ta fram ett kostnadseffektivt och flexibelt designkoncept för störelement ämnade förvindtunnelprovning av en skalmodell. Under arbetets gång undersöktes olika typer avstörelement som sedan togs fram med hjälp av CAD och additiv tillverkning. Dessa testadessedan på en skalmodell i en vindtunnel i syfte att hitta anfallsvinkeln för vilken skalmodellenöverstegrade. Mätdata jämfördes sedan med tidigare simuleringar gjorda för skalmodellen ochslutsatsen som drogs var att de framtagna störelementen hade en otillräcklig förmåga i att fåskalmodellen att överstegra, men att ytterligare modifikation av störelementens höjd och breddskulle göra modellering i CAD och additiv tillverkning till ett attraktivt framtagningskonceptför störelement ämnade för vindtunnelprovning av en skalmodell.

The main subject of the thesis is a revision of current area framing northwest part of Žerotín Square, that nowadays consists of so called White house (center for children health care and a seat of a medical school). The design is based on theoretical situation concerning the removal of White house and therefore it uses the newly existing place as a subject for new architectural solution. The solution emphasizes the completion of current block of buildings with large courtyard and corner between Žerotín Square and Veveří street, which is very important for traffic. The thesis is focusing on finding the right form, scale and functional content which would reflect the importance of the location, especially focusing on the Brno’s ring road that goes directly to Denisovy sady and accessibility of this city’s part. It also respects the design of the back side of the Red Church. The design uses the newly existing place as a location for new apartment building that reflects the scale of similar buildings in Marešov and other nearby streets and it also proposes administration building as an architectural solution for this location, which would be used as a seat for both municipal and national institutions.

The research is motivated by the need to address two major challenges in wind power integration: how to mitigate wind power fluctuation and how to ensure stability of the farm and host grid. It is envisaged that wind farm power output fluctuation can be reduced by using a specific type of buffer, such as an energy storage system (ESS), to absorb its negative impact. The proposed solution, therefore, employs ESS to solve the problems. The key research findings include a new technique for calculating the desired power output profile, an ESS charge-discharge scheme, a novel direct-calculation (optimization-based) method for determining ESS optimal rating, and an ESS operation scheme for improving wind farm transient stability. Analysis with 14 wind farms and a compressed-air energy storage system (CAES) shows that the charge-discharge scheme and the desired output calculation technique are appropriate for ESS operation. The optimal ESSs for the 14 wind farms perform four or less switching operations daily (73.2%-85.5% of the 365 days) while regulating the farms output variation. On average, the ESSs carry out 2.5 to 3.1 switching operations per day. By using the direct-calculation method, an optimal ESS rating can be found for any wind farm with a high degree of accuracy. The method has a considerable advantage over traditional differential-based methods because it does not require knowledge of the analytical form of the objective function. For ESSs optimal rating, the improvement in wind energy integration is between 1.7% and 8%. In addition, a net increase in grid steady-state voltage stability of 8.3%-18.3% is achieved by 13 of the 14 evaluated ESSs. For improving wind farm transient stability, the proposed ESS operation scheme is effective. It exploits the use of a synchronous-machine-based ESS as a synchronous condenser to dynamically supply a wind farm with reactive power during faults. Analysis with an ESS and a 60-MW wind farm consisting of stall-regulated wind turbines shows that the ESS increases the farm critical clearing time (CCT) by 1 cycle for worst-case bolted three-phase-to-ground faults. For bolted single-phase-to-ground faults, the CCT is improved by 23.1%-52.2%. / text

No description available.

The topic of the thesis is a project of roof of a multifunctional sport object with a ground-plan covering area 35x48m, and maximum height of 16m. This construction is projected for Brno and its surroundings. The project of roofing is evolved in two different variants. First one is formed by double-jointed arched latticed truss. Supporting components such as purlins, lateral and longitudal bracings, frontal column and anchorage are designed and assessed in static calculation. At the end of the thesis, comparison of both variants is elaborated. Design documentation, which consists of dispositional drawing, drawing of truss for manufacturing, drawing of indicative details and plan of anchorage, is a part of the thesis.

This diploma work considers conceptual design of aircraft in accordance in FAR 103 regulation. On the base of statistical dates has been made basic geometrical and aero-dynamical concept of a single occupant aircraft. For conception have been chosen optimal driving force and bases calculations of the load pressure and dimensions are included.

Diploma thesis is developed the design and static assessment supporting steel structure Exhibition Hall of the overall ground dimensions 47x66m with a maximum height of 15.4 meters. Layout is designed in accordance with architectural requirements. The design is considered for Brno´s area. The proposal of roof system is designed in two versions whose dimensions are identical. The first option consists of a two-aisle hall object, parabolic truss girder, pin supported on fixed columns. The second variant also two-aisle building with truss frame structure assessed in static calculation. At the end of the thesis, comparison of both variants is elaborated. Design documentation, which consist layout drawing, drawing of truss for manufacturing, drawing indicative details and plan of anchorage, is a part od thesis

Purpose - The paper presents a theoretical framework that describes the aerodynamics of a falling maple (Acer pseudoplatanus) seed. --- Methodology - A semi-empirical method is developed that provides a ratio stating how much longer a seed falls in air compared to freefall. The generated lift is calculated by evaluating the integral of two-dimensional airfoil elements using a preliminary falling speed. This allows for the calculation of the definitive falling speed using Blade Element Momentum Theory (BEMT); hereafter, the fall duration in air and in freefall are obtained. Furthermore, the input-variables of the calculation of lift are transformed to require only the length and width of the maple seed. Lastly, the method is applied to two calculation examples as a means of validation. --- Findings - The two example calculations gave percentual errors of 5.5% and 3.7% for the falling speed when compared to measured values. The averaged result is that a maple seed falls 9.9 times longer in air when released from 20 m; however, this result is highly dependent on geometrical parameters which can be accounted for using the constructed method. --- Research limitations - Firstly, the coefficient of lift is unknown for the shape of a maple seed. Secondly, the approximated transient state is yet to be verified by measurement. --- Originality / Value - The added value of this report lies in the reduction of simplifications compared to BEMT approaches. In this way a large amount of accuracy is achieved due to the inclusion of many geometrical parameters, even though simplicity is maintained. This has been accomplished through constructing a simple three-step method that is fundamental and essentially non-iterative.

<p>The objective of this research was to develop stability enhancing design features for aeroengine centrifugal compressors. The motivation for this research is based on climate change and fuel-efficiency concerns, which call for improvements in achievable pressure ratios and surge margins. Specifically, this research aimed to develop diffuser recirculation channels and provide more insight into their design space. These channels are passive casing treatments in the diffuser and have been successfully demonstrated to improve stage surge margin. Diffuser recirculation channels are secondary flow paths that connect an opening near the diffuser inlet to one further down in the passage. Flow is recirculated by relieving the static pressure differential between the two openings. The basic design concept of these features is to add blockage upstream of the diffuser inlet, reducing the amount of diffusion in the vaneless space. In addition, channel geometries can be optimized to specifically target adverse flow properties, such as high incidence on the diffuser vane leading edge.</p> <p><br></p> <p>This design development was purely computational and served as the first approach to implementation of these features in a future generation of the Centrifugal Stage for Aerodynamic Research (CSTAR) at the Purdue Compressor Research Lab. Design development consisted of a computational design study, which quantified the effects of changing diffuser recirculation channel geometries on stage stability and performance metrics. Moreover, the CFD model for this future configuration of CSTAR was created and served as the baseline comparison for design iterations. The design study was comprised of controlled variation of channel geometry parameters and iterative solving of those cases in unsteady full stage single passage CFD models. Further design optimization studies were completed on specific down-selected recirculation channel geometry configurations. In total, 16 unsteady CFD cases with varied geometry configurations and 43 steady models were solved. Once a final optimized design was confirmed, a pressure characteristic at 100 % corrected design speed was generated. Compared to the baseline speed line, the implementation of diffuser recirculation channels resulted in a more gradual numerical surge and apparent numerical surge margin enhancement. Furthermore, the variation in incidence at the diffuser vane leading edge near the shroud was significantly reduced with diffuser recirculation. For the baseline compressor, incidence grew by about 70 degrees from the design aerodynamic loading to numerical surge at that location. However, flow stabilization due to diffuser 16 recirculation resulted in a change of approximately 2 degrees through that range. In conclusion, a first approach design recommendation for diffuser recirculation channels is CSTAR was generated through computational studies. Using this recommendation, diffusers with this recirculation channel design can be manufactured and tested for experimental concept validation.  </p>