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| 1 | New perspective in statistical modeling of wall-bounded turbulence显示文摘Despite dedicated effort for many decades,statistical description of highly technologically important wall turbulence remains a great challenge.Current models are unfortunately incomplete,or empirical,or qualitative.After a review of the existing theories of wall turbulence,we present a new framework,called the structure ensemble dynamics (SED),which aims at integrating the turbulence dynamics into a quantitative description of the mean flow.The SED theory naturally evolves from a statistical physics understanding of non-equilibrium open systems,such as fluid turbulence, for which mean quantities are intimately coupled with the fluctuation dynamics.Starting from the ensemble-averaged Navier-Stokes(EANS) equations,the theory postulates the existence of a finite number of statistical states yielding a multi-layer picture for wall turbulence.Then,it uses order functions(ratios of terms in the mean momentum as well as energy equations) to characterize the states and transitions between states.Application of the SED analysis to an incompressible channel flow and a compressible turbulent boundary layer shows that the order functions successfully reveal the multi-layer structure for wall-bounded turbulence, which arises as a quantitative extension of the traditional view in terms of sub-layer,buffer layer,log layer and wake. Furthermore,an idea of using a set of hyperbolic functions for modeling transitions between layers is proposed for a quantitative model of order functions across the entire flow domain.We conclude that the SED provides a theoretical framework for expressing the yet-unknown effects of fluctuation structures on the mean quantities,and offers new methods to analyze experimental and simulation data.Combined with asymptotic analysis,it also offers a way to evaluate convergence of simulations.The SED approach successfully describes the dynamics at both momentum and energy levels, in contrast with all prevalent approaches describing the mean velocity profile only.Moreover,the SED theoretical framework is general,independent of the flow system to study, while the actual functional form of the order functions may vary from flow to flow.We assert that as the knowledge of order functions is accumulated and as more flows are analyzed, new principles(such as hierarchy,symmetry,group invariance,etc.) governing the role of turbulent structures in the mean flow properties will be clarified and a viable theory of turbulence might emerge. | Zhen-Su She Xi Chen You Wu Fazle Hussain | 2010 | Acta Mechanica Sinica2010，26，6： | 13 |
| 2 | Incorporating boundary constraints to predict mean velocities in turbulent channel flow显示文摘We derive exact near-wall and centerline constraints and apply them to improve a recently proposed LPR model for finite Reynolds number(Re) turbulent channel flows.The analysis defines two constants which are invariant with Re and suggests two more layers for incorporating boundary effects in the prediction of the mean velocity profile in the turbulent channel.These results provide corrections for the LPR mixing length model and incorrect predictions near the wall and the centerline.Moreover,we show that the analysis,together with a set of well-defined sensitive indicators,is useful for assessment of numerical simulation data. | WU You CHEN Xi SHE ZhenSu HUSSAIN Fazle | 2012 | Science China(Physics,Mechanics & Astronomy)2012，55，9： | 4 |
| 3 | Holographic particle velocimetry:a 3D measurement technique for vortex interactions,coherent structures and turbulence显示文摘 | Meng Hui Hussain Fazle | 1991 | Fluid Dynamics Research1991，8，14： | 1 |
| 4 | Connective tissue growth factor expression hints at aggressive nature of colorectal cancer显示文摘BACKGROUND Connective tissue growth factor(CTGF)is a mediator of transforming growth factor-beta signaling and plays a key role in connective tissue remodeling,inflammatory processes and fibrosis in various illnesses including cancer.AIM To investigate the role of CTGF in colorectal cancer(CRC)progression and to compare the CTGF expression with different clinicopathological parameters.METHODS Real-time polymerase chain reaction,immunohistochemistry and Western blotting was performed to evaluate the CTGF expression and the results were statistically analyzed against the clinicopathological variables of patient data using STATA software version 16.RESULTS CTGF expression levels in tumor specimens were significantly higher than their paired normal specimens.The higher protein expression levels showed a significant association with smoking,staging,tumor grade,invasion depth,necrosis of tumor tissue,and both lymphovascular and perineural invasion.As per the cox regression model and classification tree analysis,tumor-nodemetastasis stage and perineural invasion were important predictors for CTGF expression and prognosis of CRC patients.Survival analysis indicated that CTGF overexpression was associated with poorer overall and disease-free survival.CONCLUSION Expression of CTGF was increased in CRC and was linked with poor overall and disease-free survival of CRC patients.These findings support prior observations and thus CTGF may be a possible prognostic marker in CRC. | Ishrat Parveiz Bhat Tahseen Bilal Rather Irfan Maqbool Gowhar Rashid Kulsum Akhtar Gulzar A Bhat Fazl Q Parray Besina Syed Ishrat Younas Khan Mohsin Kazi Muhammad D Hussain Mudassar Syed | 2022 | World Journal of Gastroenterology2022，28，5： | 1 |
| 5 | Coherent structure dynamics in near-wall turbulence显示文摘 | Wade Schoppa Fazle Hussain | 2000 | Fluid Dynamics Research2000，26，2： | 1 |
| 6 | New scaling for compressible wall turbulence显示文摘Classical Mach-number(M) scaling in compressible wall turbulence was suggested by van Driest(Van Driest E R.Turbulent boundary layers in compressible fluids.J Aerodynamics Science,1951,18(3):145-160) and Huang et al.(Huang P G,Coleman G N,Bradshaw P.Compressible turbulent channel flows:DNS results and modeling.J Fluid Mech,1995,305:185-218).Using a concept of velocity-vorticity correlation structure(VVCS),defined by high correlation regions in a field of two-point cross-correlation coefficient between a velocity and a vorticity component,we have discovered a limiting VVCS as the closest streamwise vortex structure to the wall,which provides a concrete Morkovin scaling summarizing all compressibility effects.Specifically,when the height and mean velocity of the limiting VVCS are used as the units for the length scale and the velocity,all geometrical measures in the spanwise and normal directions,as well as the mean velocity and fluctuation(r.m.s) profiles become M-independent.The results are validated by direct numerical simulations(DNS) of compressible channel flows with M up to 3.Furthermore,a quantitative model is found for the M-scaling in terms of the wall density,which is also validated by the DNS data.These findings yield a geometrical interpretation of the semi-local transformation(Huang et al.,1995),and a conclusion that the location and the thermodynamic properties associated with the limiting VVCS determine the M-effects on supersonic wall-bounded flows. | PEI Jie CHEN Jun FAZLE Hussain SHE ZhenSu | 2013 | Science China(Physics,Mechanics & Astronomy)2013，56，9： | 1 |
| 7 | Suitable energy platform significantly improves charge separation of g-C3N4 for CO2 reduction and pollutant oxidation under visible-light显示文摘The photocatalytic activities of g-C3N4 can be significantly improved by increasing life time of the photogenerated charges. Here, in this work we introduced TiO2 as proper energy platform to accept the photogenerated electrons from g-C3N4 during photocatalysis. The nanophotocatalysts formed from the combination of a suitable amount of TiO2 nanoparticles and g-C3N4 nanosheets showed 8.75 and 4.22% enhancement in photocatalytic activities for CO2 reduction and 2-chlorophenol(2-CP) degradation under visible light illumination as compared to bare g-C3N4. Based on the surface photovoltage spectra, photoluminescence spectra and examination of formed hydroxyl radicals, it was confirmed that these enhanced photoactivities were attributed to the much-improved charge separation via the electron transfer from g-C3N4 to TiO2. From trapping experiments,it was found that hydroxyl radicals were the major species involved in the photocatalytic degradation of 2-CP.This study is helpful to synthesize efficient photocatalysts to cope with energy and environmental issues. | Amir Zada Nauman Ali Fazle Subhan Natasha Anwar Muhammad Ishaq Ali Shah Muhammad Ateeq Zahid Hussain Khair Zaman Momin Khan | 2019 | Progress in Natural Science:Materials International2019，29，2： | 1 |
| 8 | Experimental studies of surface waves inside a cylindrical container显示文摘 | CUNBIAO LEE HUAIWU PENG HUIJING YUAN JIEZHI WU MINGDE ZHOU FAZLE HUSSAIN | 2011 | Journal of Fluid Mechanics2011，，： | 1 |
| 9 | Holographic particle velocimetry: a 3D measurement technique for vortex interactions, coherent structures and turbulence 显示文摘 | Fazle Hussain | 1991 | Fluid Dynamics Research1991，8，： | 1 |
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