Sökning: "turbulent boundary layer measurements"

Visar resultat 26 - 30 av 51 avhandlingar innehållade orden turbulent boundary layer measurements.

1. 26. Active Control and Modal Structures in Transitional Shear Flows

   Författare :Onofrio Semeraro; Dan Henningson; Bernd Noack; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Flow control; flat-plate boundary layer; optimal controllers; model reduction; turbulent jet; POD; DMD; Koopman modes;

   Sammanfattning : Flow control of transitional shear flows is investigated by means of numerical simulations. The attenuation of three-dimensional wavepackets of Tollmien-Schlichting (TS) and streaks in the boundary layer is obtained using active control in combination with localised sensors and actuators distributed near the rigid wall. LÄS MER

3. 27. The Arctic Atmosphere : Interactions between clouds, boundary-layer turbulence and large-scale circulation

   Författare :Georgia Sotiropoulou; Michael Tjernström; Joseph Sedlar; Susanne Crewell; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arctic; mixed-phase clouds; thermodynamic structure; Arctic inversion; cloud-surface interactions; seasonal transition; IFS model; LES; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

   Sammanfattning : Arctic climate is changing fast, but weather forecast and climate models have serious deficiencies in representing the Arctic atmosphere, because of the special conditions that occur in this region. The cold ice surface and the advection of warm air aloft from the south result in a semi-continuous presence of a temperature inversion, known as the “Arctic inversion”, which is governed by interacting large-scale and local processes, such as surface fluxes and cloud formation. LÄS MER

4. 28. Flow and Mixing of Pulp Suspensions

   Författare :Johan Pettersson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; flow behaviour; boundary-layer; Medium Consistency MC ; mixing; yield stress; suspension; pulp; Laser Doppler Anemometry LDA ; turbulence; fibre;

   Sammanfattning : When producing pulp and paper, pulp suspensions are treated in a number of unit operations at medium consistency (MC) concentrations (3-15% by weight). Pulp suspensions at these concentrations behave as solids at low shear rates, but at sufficiently high shear rates they start to flow and can even be made to act as water. LÄS MER

5. 29. Acoustical Characteristics of Aircraft Panels

   Författare :Bilong Liu; Leping Feng; Jie Pan; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Acoustics; sound transmission loss; stiffener; stiffening; aircraft panel; cylindrical shell; turbulent boundary layer; TBL; noise; sound radiation; Acoustics; Akustik;

   Sammanfattning : A deterministic approach based on a modal expansion and modal receptance method has been developed to evaluate the airborne sound insulation of aircraft panels with stringer and ring frame attachments. Furthermore, this method was extended to predict the noise radiation of stiffening panel subjected to TBL excitation. LÄS MER

7. 30. Turbulent Structure of the Marine Atmospheric Boundary Layer and Its Implications for the Inertial Dissipation Method

   Författare :Anna Sjöblom; Jørgen Højstrup; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; Geovetenskap; Earth sciences; Geovetenskap; Meteorology; meteorologi;

   Sammanfattning : In order to improve climate- and weather forecasting models, a better knowledge of the physical processes taking place in the lowest part of the atmosphere over the oceans is essential. In these models it is often assumed that the atmospheric boundary layer over sea behaves in the same way as that over land. LÄS MER