The velocity components of the high temperature high speed flow produced by a simulative device were diagnosed by single-line hydroxyl tagging velocimetry. The simulative device was driven by H2/air combustion gas, worked like a shock tube, held about 10-ms. The HTV tagging lines were put after the exit of device, and the experimental images at flow’s different regions were acquired through changing the tagging lines’ positions corresponding to the exit of device. And the velocity components along the device axis on tagging lines were calculated from the images. The results indicated that the velocity values of the flow in compress region were much slower than those in expansion region. Between the flow’s first expansion and compress regions, the velocity values at center were higher than those at both sides, but in the flow’s second expansion region, the velocity values at center were slower than that at both sides.
Laser induced fluorescence has the potential to get two dimension temperature and concentration map in combustion. For understanding the fluorescence technology exactly, A detailed experiment has been developed to investigate the fluorescence spectrum. The time variation of spectrum is first presented by changing the pump-probe time delay. And this is followed by demonstrate the response of fluorescence to laser excitation. As showed by the experiment result, The intensity ratio of the (1, 1) and (0, 0) fluorescence band was varied both with time and the exiting laser line, we attribute this phenomenon to the difference rotational distribution of excited OH. And the new rule, which exciting a specific rotational level in the A<sup>2</sup>Σ(υ ' =1) excited state from two difference rotational levels in the X <sup>2</sup>Π(υ " = 0) ground state, was experimental confirmed, and this will be a foundation to the future two line laser induced fluorescence thermometry.
In TCP over OBS networks, the parameters from both of TCP and OBS layers will affect the network performance when
supporting the upper layer applications, such as Grid application. According to our previous work, we found that TCP
window is the key limitation for such a network to support Grid application. The embedded AIMD model of TCP is too
conservative. Especially in the network with high bandwidth-delay product scenario, it will take TCP a long time to
increase the TCP window according to the slow start and the congestion avoidance rules. In this paper, according to the
established analytical model, the TCP window size is optimized in Grid over OBS network. The analytical results show
that the optimization of TCP window can improve the TCP throughput significantly.
Optical burst switching (OBS) is thought to be the best way to adapt the bursty IP traffic over optical WDM networks.
It provides statistical multiplexing gains and avoids long end to end setup time of traditional virtual circuit configuration.
However, under the current and foreseeable limitations of optical technology, performance of OBS is mainly hampered
at network nodes by burst contention. The contention is serious constraints on the capacity of OBS networks. A leading
source of contention is the congestion at congested links where a limited number of wavelengths are shared by a lot of
bursts. These congested links are stemming from burst routing algorithms. In this paper, we studied on routing path
competition phenomenon. We proposed a differentiated QoS aware multipath routing algorithm for OBS networks. This
algorithm is evaluated through extensive numerical studies over a typical topology--the 14-node NSFnet. Results show
that it outperforms the existing algorithms in terms of burst blocking probability and link utilization.
Future WDM optical networks are foreseen to be more dynamic and sensitive to failures. Therefore, dynamic service
provisioning with network survivability becomes a critical requirement for network planning and management. The
concept of <i>protected working capacity envelope </i>(PWCE) is attractive because it does not need protection resources to be
dynamically configured thereby simplifying network management and reducing processing overheads. In this paper, we
consider a <i>p</i>-Cycle-based Strategy for adaptive PWCE (protected working capacity envelope) design where PWCE can
adaptively change with dynamically changing traffic. The blocking performance of this new strategy is compared to that
of <i>p</i>-Cycle-based PWCE under a dynamic and non-uniform traffic model. The results show that the new strategy can
adapt well to dynamic traffic demands that are non-uniform among the network nodes.
Under the current and foreseeable limitations of optical technology, performance of the next generation optical network is mainly hampered at the network node by resource contention. Existing work addresses contention resolution mostly in the wavelength domain (as wavelength conversion, WC), the time domain (buffering by using fiber delay lines, FDLs, the space domain (as deflection routing), and the burst domain (as segmentation). In this paper, a new architecture of optical networks-the server view based on optical networks is proposed. From the point of this new architecture, the network can be modeled as a server system with three type servers-the access server, the node server and the link server. The network performances such as cost, energy consume and network capacity can be affected by the capability of these three type servers. Unlike existing research activities that are focused on the node server design, we present the Dual fiber link (the link server solution) and IP calking (the access server solution) to ease the resource contention. To evaluate the performance of the proposed methods, computer simulations are conducted. The simulation results show these solutions can reduce the contention effectively with existing commercial devices.