A general methodology is developed for simulating complicated reacting flow problems. This method combines the large-eddy simulation (LES) technique with the existing probability density function (PDF) approach for turbulent reacting flows and provides a closed form representation for all terms that are involved in the simulations. Some other issues related to this problem are also discussed.

Polynucleotide immunisation with the E7 gene of human papillomavirus (HPV) type 16 induces only moderate levels of immune response, which may in part be due to limitation in E7 gene expression influenced by biased HPV codon usage. Here we compare for expression and immunogenicity polynucleotide expression plasmids encoding wild-type (pWE7) or synthetic codon optimised (pHE7) HPV16 E7 DNA. Cos-1 cells transfected with pHE7 expressed higher levels of E7 protein than similar cells transfected with pW7. C57BL/6 mice and F1 (C57x FVB) E7 transgenic mice immunised intradermally with E7 plasmids produced high levels of anti-E7 antibody. pHE7 induced a significantly stronger E7-specific cytotoxic T-lymphocyte response than pWE7 and 100% tumour protection in C57BL/6 mice, but neither vaccine induced CTL in partially E7 tolerant K14E7 transgenic mice. The data indicate that immunogenicity of an E7 polynucleotide vaccine can be enhanced by codon modification. However, this may be insufficient for priming E7 responses in animals with split tolerance to E7 as a consequence of expression of E7 in somatic cells.

While turbine rim sealing flows are an important aspect of turbomachinery design, affecting turbine aerodynamic performance and turbine disk temperatures, the present understanding and predictive capability for such flows is limited. The aim of the present study is to clarify the flow physics involved in rim sealing flows and to provide high-quality experimental data for use in evaluation of computational fluid dynamics (CFD) models. The seal considered is similar to a chute seal previously investigated by other workers, and the study focuses on the inherent unsteadiness of rim seal flows, rather than unsteadiness imposed by the rotating blades. Unsteady pressure measurements from radially and circumferentially distributed transducers are presented for flow in a rotor–stator disk cavity and the rim seal without imposed external flow. The test matrix covered ranges in rotational Reynolds number, Re∅, and nondimensional flow rate, Cw, of 2.2–3.0 × 106 and 0–3.5 × 103, respectively. Distinct frequencies are identified in the cavity flow, and detailed analysis of the pressure data associates these with large-scale flow structures rotating about the axis. This confirms the occurrence of such structures as predicted in previously published CFD studies and provides new data for detailed assessment of CFD models.

The increase of the thrust/weight ratio of aircraft engines is extremely restricted by different 3-D flow loss mechanisms. One of them is the corner separation that can form at the junction between a blade suction side and a hub or shroud. In this paper, in order to further investigate the turbulent characteristics of corner separation, large-eddy simulation (LES) is conducted on a compressor cascade configuration using NACA65 blade profiles (chord based Reynolds number: 3.82 × 10 5), in comparison with the previous obtained experimental data. Using the shear-improved Smagorinsky model as subgrid-scale model, the LES gives a good description of the mean aerodynamics of the corner separation, especially for the blade surface static pressure coefficient and the total pressure losses. The turbulent dynamics is then analyzed in detail, in consideration of the turbulent structures, the one-point velocity spectra, and the turbulence anisotropy. Within the recirculation region, the energy appears to concentrate around the largest turbulent eddies, with fairly isotropic characteristics. Concerning the dynamics, an aperiodic shedding of hairpin vortices seems to induce an unsteadiness of the separation envelope.