Qualitative and Quantitative Investigation of Laminar-to-Turbulent Transition in Steady and Unsteady Boundary Layers

by Muhammed Raşit Çevikalp | Dec 19, 2022

Project Title: Qualitative and Quantitative Investigation of Laminar-to-Turbulent Transition in Steady and Unsteady Boundary Layers
Project Type: TÜBİTAK-ARDEB 1001
Project Coordinator: Prof. Dr. Veysel Şadan Özgür Kırca

In this research project, major purpose is the qualitative and quantitative investigation of laminar-to-turbulent transition in the case of steady non-uniform (spatially developing) boundary layers, as well as unsteady (temporally developing) boundary layers. In the scope of the project, typical geometric, kinematic and dynamic conditions in the boundary layer during laminar-to-turbulent transition, coherent structures related with these conditions, the spatial and temporal variation of instantaneous flow parameters (velocity and pressure) associated with emergence and development of turbulence in the boundary layer are investigated. Both physical modeling and numerical modeling methods are employed in the project. In the context of physical modeling, experiment are conducted in the lab by use of Particle Image Velocimetry (PIV) and flow visualization via laser sheet to investigate laminar-to-turbulent transition in two different types of boundary layers; non-uniform steady flow, and unsteady boundary layer under progressive waves.The second method to be applied in the project is the Direct Numerical Simulation (DNS). The DNS technique enables modeling of turbulent or transitional flows without the necessity of any empirical approach or simplification. To this end, ITU-UHeM supercomputers are employed for numerical modeling. When completed, the results of project will help to better understand the laminar-to-turbulent transition in developing boundary layers.

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İTÜ Faculty of Civil Engineering

It can be accepted that the history of ITU Civil Engineering Faculty was commenced in 1727 by the establishment of Humbarahane during the era of Damat İbrahim Paşa. However, this attempt was to no avail due to the martyrization of the studwents of this school by the Janissaries.

In 1734, during the grand viziership of Topal Osman Paşa, classes related to Civil Engineering was being taught in Hendesehane, which was founded in Üsküdar. Similarly, this school was also closed after three years due to the opposition of the Janissaries. The reasons of the tragedy that occured in Battle of Chesma, 1770 were inadequacy of the ships and the ignorance of the Ottoman Navy.

Although the Atlantic Map (1513) and the Map of Europe and the Mediterranean Sea (1523) by Piri Reis were the leading pieces of the era, Ottoman viziers were so ignorant that they claimed it was impossible for the Russian Baltic Fleet to reach the Mediterranean Sea assuming that there were no sea connection. With the proposal from Gazi Hasan Paşa and Baron de Tott, Mühendishane-i Bahri-i Humayun was established during the time of Sultan Mustafa III, aiming to train naval construction engineers. Since Ottoman Empire did not have any engineering schools at the time, military engineering classes were taught by French engineers beginning from 1784. French lecturers had to return to their country in 1788 with the increasing suppression from Austria and Russia, which were unwilling for the development and thriving of Ottoman Empire. In 1759, during the Grand Viziership of Koca Ragıp Paşa, Humbarahane was reopened in Karaağaç, Haliç (Golden Horn) and continued to teach even though it was incompetent. In 1792, Lağımcı Ocağı and Humbaracı Ocağı (Guild of Sappers) were established.