High-order accurate p-multigrid discontinuous Galerkin solution of the Euler equations

Discontinuous Galerkin (DG) methods have proven to be perfectly suited for the construction of very highorder accurate numerical schemes on arbitrary unstructured and possibly nonconforming grids for a wide variety of applications, but are rather demanding in terms of computational resources. In order to improve the computational efficiency of this class of methods a p-multigrid solution strategy has been developed, which is based on a semi-implicit Runge–Kutta smoother for high-order polynomial approximations and the implicit Backward Euler smoother for piecewise constant approximations. The effectiveness of the proposed approach is demonstrated by comparison with p-multigrid schemes employing purely explicit smoothing operators for several 2D inviscid test cases

Ventromedial prefrontal damage causes a pervasive impairment of episodic memory and future thinking.

The ability to project oneself into the past and future to relive or pre-live personal experiences, known as mental time travel (MTT), is associated with activity in a core network of brain regions involving the ventromedial prefrontal cortex (vmPFC). We investigated whether (1) vmPFC is crucial for MTT, and (2) whether vmPFC is selectively involved in the construction of self-relevant events or also mediates construction of events happening to others. Patients with lesions to vmPFC (vmPFC patients) and healthy controls remembered personal past events and imagined personal future events across different timeframes, and imagined events to happen to a close or a distant other. Compared to the controls, vmPFC patients were impaired at constructing both past and future events, indicating that vmPFC is critical for MTT. vmPFC patients' ability to imagine personal future events was related to patients' temporal discounting rates. Patients, however, were also impaired at imagining other-related events, suggesting that self-relevance may not be a critical factor in explaining vmPFC's involvement in MTT. We suggest that vmPFC is crucial for the imagination of complex experiences alternative to the current reality, which serves construction of both self-relevant and other-relevant events

DISCONTINUOUS GALERKIN SOLUTION OF THE EULEREQUATIONS USING AN h-MULTIGRID METHOD

8th.World Congress on Computational Mechanics (WCCM8) 5th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008) June 30 –July 5, 2008 Venice, Ital

On the effects of leaning and bowing techniques on turbine cascades flow field: experimental and numerical analysis

The paper deals with the internal passage and downstream flow field effects produced by the application of 3D design techniques on linear turbine cascades. In particular, the two design techniques generally called “lean” and “lean compound” (or “bowing”), have been applied to the same profile. The investigation has been carried out by means of both numerical and experimental tools. An extensive experimental campaign was originally performed on cylindrical straight blades in the transonic wind tunnel of LFM (Laboratorio di Fluidodinamica della Macchine) of the Politecnico di Milano. The large data base available has been then used as set of test cases in order to validate the set up of a CFD tool. Subsequently a leaned cascade has been investigated by means of both methods. Finally the effects of blade bowing have been analysed only with a computational approach. The contemporary application of the two tools allows to get deeply inside of the effects produced by the three different blade design techniques