نجم الدين محمد الشرفي

Research interests
 
 Numerical analysis and simulations in mechanics:

• Finite element methods. Applications: fluid mechanics (Navier-Stokes), structural mechanics in large deformations, damage of materials.
• Finite element methods for variational inequalities. Applications: unilateral contact mechanics.
• Spectral elements method, domain decomposition, mortar element method. Applications: porous media, Navier-Stokes equations,  ...

Shape optimization and inverse problems:

• Cracks detection by electrostatic measurements.
• Reconstruction algorithms by level set and optimal design methods.
• Eigenvalues problems in nonsmooth domains: buckling, multi-cracked materials, densification of small heterogeneities in vibrating materials.
• Topology optimization  in structural mechanics.

A posteriori analysis:

• Adaptive strategies for numerical computations in partial differential equations.

 
 
Ph.D. and Masters directed
 

• Azhar Al salem (since 2015): A time dependent of Vorticity Velocity  and Pressure  formulation of Navier-Stokes problem.
• Heya Eddoussari: Spectral discretisation of Stokes problem (2013)
• Ibtissam Elharbi:  Spectral discretisation of Laplace equation (2012)
• SihemTrabelsi: Spectral Discretisation of Vorticity Velocity  and Pressure  formulation of Navier-Stokes axisymetric problem  (2010)
• Haithem Abbes : Parallelization of Mortar Spectral Element Method. (2005)
• Ines Ben Ommrane : A posteriori analysis of the spectral element discretization of the one-dimensional heat equation  (2005).

 
Reviewed Publications
 

• M. EL HAJJI, N. CHORFI, M. JLELI MATHEMATICAL MODEL FOR A MEMBRANE    BIOREACTOR PROCESS. Electronic Journal of Differential Equations. Vol. 2015, No. 315, 1-7, (2015).
• W. Oueslati ,  M. Ammar, N. Chorfi Quantitative XRD Analysis of the Structural Changes of Ba-Exchanged Montmorillonite: Effect of an in Situ Hydrous Perturbation. Minerals 2015, 5, 507-526; doi:10.3390/min5030507
• N. Chorfi. Mortar spectral element discretization of the Stokes problem in domain with corners. Boundary Value Problems DOI 10, 1186/s13661-015-0387-4, (2015).
• F. Bouzeffour, N. Chorfi. The non-symmetic lommel function transform. Integral Transforms, and Special Function, Vol. 26, No 7, 550-566, (2015).
• M. Abdelwahed, N. Chorfi, H. Maatoug. Asymptotic formulas for the identification of small inhomogeneities in a fluid medium. Electronic Journal of Differential Equations. Vol. 2015, No. 186, 1-13, (2015).
• N. Chorfi, M. Jleli. Approximation of the singularity coefficients   of an elliptic equation by mortar spectral element method. Electronic Journal of Differential Equations. Vol. 2015, No. 157, 1-13, (2015).
• M. Ammar, W. Oueslati, N. Chorfi, A. Ben Haj Amara. The water retention mechanism + + of a Cs and Na exchanged montmorillonite: effect of relative humidity and ionic radius on the interlayer. Powder Diffr, Vol. 30, No S1, 70-75 (2015).
• N. Chorfi, M. Abdelwahed, I. Ben Omrane. A posteriori analysis of the spectral element discretization of heat equation. An. S ¸t. Univ. Ovidius Constant¸a. Vol. 22, No. 3, 13-35 (2014).

·       N. Chorfi. Geometric singularities of the Stokes problem Abstract and Applied Analysis

Volume 2014 (2014), Article ID 491326

·       M. Ammar, W. Oueslati, N. Chorfi, H. Ben Rhaiem. Interlamellar Space Configuration under Variable Environmental Conditions in the Case of Ni-Exchanged Montmorillonite: Quantitative XRD Analysis. Journal of Nanomaterials Volume 2014, Article ID 284612, (2014).

• N. Chorfi, N. Abdellatif, S. Trabelsi. Spectral discretization of the axisymmetric vorticity, velocity and pressure formulation of the Navier-Stokes equations. Journal of Computational and Applied Mathematics 241,  1–18 (2013).
• K. Amoura, C. Bernardi, N. Chorfi, S. Saadi. Spectral discretization of the Stokes problem with mixed boundary conditions. Coupled Fluid Flow in Energy, Biology and Environmental Research edited by M. Ehrhardt, Progress in Computational Physics (PiCP), Volume 2 (2012).
• N. Abdellatif, N. Chorfi, S. Trabelsi. Spectral discretization of the axisymmetric vorticity, velocity and pressure formulation of the Stokes problem. SIAM  J Sci Comput (2011) 47: 419–440 DOI 10.1007/s10915-010-9446-2
• M. Azaiez, F. ben Belgacem, C. Bernardi, N. Chorfi. Spectral discretization of Darcy's equations with pressure dependent porosity. Appl. Math. Comput. Volume: 217 Issue: 5 Pages: 1838-1856 (2010).
• C. Bernardi, A. Blouza, N. Chorfi, N. Kharrat. A penalty algorithm for the spectral element discretization of the Stokes problem. Math. Model.Numer. Anal. (2010). Doi: 10.1051/m2an/2010038.
• K. Amoura, M. Azaiez, C. Bernardi, N. Chorfi, S. Saadi. Spectral element discretization of the vorticity, velocity and pressure formulation of the Navier-Stokes equations. CALCOLO, Vol 44, 167-190, (2007).
• H. Abbes, N. Chorfi, M. Jemni. Parallelization of mortar spectral element method. International Journal of Computing and Information Sciences, Vol 4, N3, 157-169, (2006).
• K. Amoura, C. Bernardi, N. Chorfi. Spectral element discretization of the vorticity, velocity and pressure formulation of the Stokes problem. Journal of Mathematical Modelling and Numerical Analysis, Vol 40, N5, 897-921., (2006).
• M. Azaiez, C. Bernardi, N. Chorfi. Spectral discretization of the vorticity, velocity and pressure formulation of the Navier-Stokes equations. Numerische Mathematik, 104, 1-26.,(2006).
• C. Bernardi, N. Chorfi. Spectral discretization of the vorticity, velocity and pressure formulation of the Stokes problem. SIAM Journal of Numerical Analysis, Vol 44, N2, 826-850., (2006).
• N. Chorfi . Handling geometric singularities by the mortar spectral element method.: Case of the Laplace equation. SIAM  Journal of Scientific Computing, Vol 18, N1, 25-48. (2003).
• C. Bernardi, N. Chorfi. Mortar spectral element methods for elliptic equations with discontinuous coefficients. Mathematical Models and Methods in Applied Sciences, Vol 12, N4, 497-524. (2002).
• F. Ben Belgacem, C. Bernardi, N. Chorfi, Y. Maday. Inf-sup conditions for the mortar spectral element discretization of the Stokes problem. Numerische Mathematik, 85, 257-281., (2000).
• N. Chorfi. Traitement de singularités géomètriques par mèthode d'éléments spectraux avec Joints. Nouvelle Thèse, Université Pierre et Marie Curie - Paris VI, (1997).

 
Participation to group committees of scientific research
 

• Since 2015 : Principal investigator of NPST project 14-Mat 739-002 Modeling numerical analysis and simulation of flows in fractured porous medias
• Since 2014: Principal investigator of the Research Group No.: RGP-1435-026

 
Community services
 

• Head of mathematics computation committee
• Member of analysis committee

 
Numerical Development
 

• Numerical resolution of elliptic problems (2D and 3D)
• Numerical resolution of Navier-Stokes problem (2D and 3D).
• Langages: Fortran, C, C++, Matlab.