A method for partitioning airspace into smaller regions based on a peak traffic-counts metric is described. The three setup steps consist of 1) creating a network flow graph, 2) creating an occupancy grid composed of grid cells of specified size for discretizing the airspace and 3) assigning the grid cells to the nodes of the network flow graph. Both the occupancy grid and the grid cell assignment to nodes are computationally realized using matrices. During the run phase of the method, the network flow graph is partitioned into its two sub-graphs and these two sub-graphs and then partitioned into their two sub-graphs, and so on till a termination criterion is met. Weights of the sub-graphs are computed by summing the number of aircraft in each grid cell associated with the nodes of the sub-graphs at each time instant. This process is accomplished by using the occupancy and assignment matrices created during the setup step. The final weight is obtained as the maximum count over a time period. Spectral bisection is then used to split the sub-graph with the maximum weight into its two sub-graphs. Recursive application of the spectral bisection method and weight computation results in the final set of sub-graphs. The grid cells associated with each sub-graph then represent the geometry of the associated sector. Results of sectorization of the airspace over the continental United States are provided to demonstrate the merits and the limitations of the method. The weighted-graph technique created larger sectors in regions of light-traffic and smaller sectors in regions of heavy-traffic. Peak traffic-counts in the sectors were found to be within the range of the Monitor Alert Parameters specified in the Enhanced Traffic Management System.

A method for the optimization of rocket combustion chamber (combustion chamber) walls with respect to the life time is presented. This method can be split into four main parts: P1) Determination of the thermal field within the combustion chamber wall and the cooling channel during the hot run phase by a steady state thermo-fluid mechanical analysis; P2) Analysis of the nonlinear deformation of the combustion chamber wall under cyclic thermal and mechanical loading using a 2d plane strain or a 2d generalized plane strain model; P3) Estimation of the life time of the combustion chamber wall by a post processing method and P4) Application of a mathematical optimization procedure (gradient free or Conjugate Gradient method). This strategy is used to analyse the thermal load induced deformation process and life time of a typical rocket combustion chamber and to optimise selected geometry parameters of the combustion chamber wall.

The simulation of the process planning is a decisive stage in the manufacturing process of a set of parts. This simulation is generally carried out by the calculation of the working dimensions (WD) according to the blueprint dimensions (BPD), to the means of production and to the machining process. The calculation and the generating of the working dimensions can be done by using different methods such as the transfer method, the dispersion method and the tolerance chart method. This article presents a system of automatic generating of the working dimensions (WD) through the tolerance chart method. From the blueprint dimensions and from the process planning proposed, the system allows the automatic generating of three graphs: the blueprint dimensions graph, the blueprint dimensions and the stock removal graph, as well as the working dimensions graph. After the drawing of the two last graphs, the dimensional chains appear in the matrix from: Y=PX. At last, the calculation of the tolerance intervals for each dimension is done from the resolution of an equation system according to the minimum economic tolerances imposed by the manufacturing process and to the weight assigned to the tolerances.

This paper reports preliminary results of simulating a synthetic jet interacting with the boundary layer flow in laminar separation. The numerical model development aimed to simulate the physical process in previous experimental investigation. A model for simulating the base flow was developed first and then extended to including the synthetic jet. The computational domain was three-dimensional and covered the exit of the synthetic jet actuator and the separation region. Large-eddy simulation (LES) was employed, and the initial and boundary conditions were defined using or referring to wind tunnel experimental results. The numerical model was verified by comparing the simulation with experimental results. Based on reasonable agreement between the numerical and experimental results, simulations were carried out to investigate the dependency of the synthetic jet's actuation on the forcing frequency, in a focused range of the lower Tollmien-Schlichting (T-S) frequencies.

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