Search results for "Drag"
showing 10 items of 179 documents
A Novel Multi-Scale Strategy for Multi-Parametric Optimization
2017
The motion of a sailing yacht is the result of an equilibrium between the aerodynamic forces, generated by the sails, and the hydrodynamic forces, generated by the hull(s) and the appendages (such as the keels, the rudders, the foils, etc.), which may be fixed or movable and not only compensate the aero-forces, but are also used to drive the boat. In most of the design, the 3D shape of an appendage is the combination of a plan form (2D side shape) and a planar section(s) perpendicular to it, whose design depends on the function of the appendage. We often need a section which generates a certain quantity of lift to fulfill its function, but the lift comes with a penalty which is the drag. Th…
Evaluation of the Measuring Active Drag system usability: An important step for its integration into training sessions
2010
This paper is the first stage of an iterative process aiming at the (re)design of a training device for swimming. The purpose of this study was to evaluate the usability of the Measuring Active Drag (MAD) system, a technical device for biomechanical evaluation and performance analysis. To do so, this study examines real activity of elite swimmers using this system. It was conducted within an activity-centred approach: the course-of-action technological research programme. Three international male swimmers volunteered to participate in the study. Two types of data were collected: (a) video recordings, and (b) verbalisations during post-protocol interviews. The data were processed in two step…
The effect of peatland drainage and restoration on Odonata species richness and abundance
2015
Background Restoration aims at reversing the trend of habitat degradation, the major threat to biodiversity. In Finland, more than half of the original peatland area has been drained, and during recent years, restoration of some of the drained peatlands has been accomplished. Short-term effects of the restoration on peatland hydrology, chemistry and vegetation are promising but little is known about how other species groups apart from vascular plants and bryophytes respond to restoration efforts. Results Here, we studied how abundance and species richness of Odonata (dragonflies and damselflies) respond to restoration. We sampled larvae in three sites (restored, drained, pristine) on each o…
Using CFD to derive reduced order models for heat transfer in particle curtains
2015
3–D Eulerian–Eulerian CFD is used to simulate convective heat transfer in free falling particle curtains. Total heat loss for curtaining particles is compared to heat loss for isolated single particles. Spherical silica particles with density of 2,634 kg/m³ at 400 K (200 µm, 400 µm and 600 µm) flow at approximately 0.041 kg/s to 0.2 kg/s through a narrow slot in a rectangular box (0.45 m × 0.9 m × 0.225 m) filled with ambient air. The slot sizes through which the particles enter the rectangular box were 10 to 80 mm wide. Modifying the slot size at 0.041 kg/s for 400 µm particles can lead to 13% increases in rates of convective heat transfer per unit mass. A reduced order model was developed…
Adaptive control of a seven mode truncation of the Kolmogorov flow with drag
2009
Abstract We study a seven dimensional nonlinear dynamical system obtained by a truncation of the Navier–Stokes equations for a two dimensional incompressible fluid with the addition of a linear term modelling the drag friction. We show the bifurcation sequence leading from laminar steady states to chaotic solutions with increasing Reynolds number. Finally, we design an adaptive control which drives the state of the system to the equilibrium point representing the stationary solution.
Dracocephalum ruyschiana L. (Numerne, 1888)
1888
Nordischer Drachenkopf finden in lichte Kieferwaldhouge Nemerno. /// Ruiša pūķgalve, atradne: gaiša priežu meža nogāne Numernē. /// Northern Dragon-head, deposit: light pine forest slope in Numerne. [Attēls no LU Muzeja kolekcijas Herbarium Balticum (RIG I); (BOT2791_12)]
Dracocephalum ruyschiana L. (Numerne)
1936
Ruiša pūķgalve; Atradne: Latgalē, Numernē, austrumos no Puriņu mežsarga mājām. /// Northern Dragon-head, deposit: In Latgale, Numerne, east of the Purin forest rangers home. [Attēls no LU Muzeja kolekcijas Herbarium Latvicum (RIG II); (BOT1029_13)]
Dracocephalum ruyschiana L. (Suntažu pagasts)
1938
Ruiša pūķgalve, atradne: Rīgas apriņķa Suntažu pagasta Lielo Kangaru klajās dienvidu nokares piekājē, 43. km no Rīgas. /// Northern Dragon-head, deposit: Riga District Suntažu parish on the southern slope of Lielie Kangari, 43 km from Riga. [Attēls no LU Muzeja kolekcijas Herbarium Latvicum (RIG II), (BOT1029_26) ]
Dracocephalum ruyschiana L. (Ogres Kangari pie Ikšķiles)
1923
Nordischer Drachenkopf finden in sonnigers Abhang des Grandhügels am Ogre - Kanger bei Üxküll. /// Ruiša pūķgalve, atradne: liela kalna saulaina nogāze Ogres Kangaros pie Ikšķiles. /// Northern Dragon-head, deposit: sunny slope of the grand hill on the Ogre - Kanger near Ikskil. [Attēls no LU Muzeja kolekcijas Herbarium Balticum (RIG I); (BOT 2791_7)]
Dracocephalum ruyschiana L. (Grants-kalns pie Ogres Kangariem, Rīgas apriņķis)
1895
Nordischer Drachenkopf finden in Livland, Kreis Riga, Hügel, genannt "Grant-kalns" am Oger Kanger zwischen Üxkull und Oger. /// Ruiša pūķgalve, atradne: Livlande, Rīgas apriņķis, tā sautā "Grants-kalns" pie Ogres Kangariem starp Ikšķili un Ogri. /// Northern Dragon-head, deposit: Riga district, hill, called "Grant-kalns" on the Ogres Kangar between Ikskil and Ogre. [Attēls no LU Muzeja kolekcijas Herbarium Balticum (RIG I); (BOT2791_11)]