Function Reference

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flu_mass

Syntax: [vme]=flu_mass(ie,vcore)
Description: Computation of the elementary fluid mass matrix
Comments: none

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flu_residual

Syntax: [vrese]=flu_residual(ie,Delta_t,conec,vsol,vpres,vcore0,vflue,wxe,gamm1)
Description: Computation of the elementary fluid residual
Comments: Calculation in two steps according to the Lax-Wendroff scheme

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fluid

Syntax: fluid
Description: Computation of all fluid characteristics at a given time step
Comments: All fluid models are computed: A-, B- and C-models

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flux

Syntax: flux(vsol,pres,wx)
Description: Computation of the elementary fluid convective flux
Comments: This flux is corrected with regards to moving mesh capabilities

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fsi_display

Syntax: fsi_display
Description: Script dedicated to the plotting management
Comments: This script is called inside the main time loop of 'main_fsi.m'

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initialize_data_fluid

Syntax: initialize_data_fluid
Description: Parameters initialization for the fluid part: geometry, mesh, fluid properties, initial and boundary conditions
Comments: none

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initialize_data_structure

Syntax: initialize_data_structure
Description: Parameters initialization for the structure part: mass, rigidity and initial conditions
Comments: none

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integ

Syntax: integ(vsol,x,conec)
Description: Script used to proceed to the integration on the fluid domain of the mass, momentum and energy
Comments: Procedure based on the finite element integration

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Lax_Wendroff

Syntax: [vsol, vflux]=Lax_Wendroff(gamm1,ifct,Delta_t,vsol,vpres,wx, conec, vcor_n, vcor_np1,number)
Description: Script for fluid resolution in time based on the Lax-Wendroff scheme
Comments: This script includes a shock capturing technique to ensure spatial stability of all fluid variables

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main_fsi

Syntax: main_fsi
Description: Main script  dedicated to fluid-structure interaction (piston-chamber application)
Comments: It considers three fluid models:
   o A-model perfect gas law with adiabaticity condition: P.V^gamma = cst
   o B-model piston analogy model
   o C-model 1D compressible fluid flow evolution with three fluid flow formulations:
               0) Eulerian
               1) Lagrangian
               2) ALE (Arbitrary Lagrangian Eulerian)
 A shock capturing technique is used to ensure fluid spatial stability for the C-model.

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move_mesh

Syntax: [wx,vcor_n,vcor_np1]=move_mesh(formulation,Delta_t,du,u_dot_t,vsol,vcor_n,vcor_np1)
Description: Script dedicated to the fluid mesh deformation at each time time
Comments: Only necessary for the C-model

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post_treatment

Syntax: post_treatment
Description: Script for post-processing at the end of the script 'main_fsi.m'
Comments: none

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pressure

Syntax: [vpres]=pressure(R,vtemp,vsol)
Description: Computation of the pressure on each node of the fluid model, according to the perfect gas law
Comments: Only necessary for the C-model

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shock_capture

Syntax: [du]=shock_capture(ifct,vcor,conec,vmgn,vmgnp1,vres,vsol,xlumpm,number)
Description: Shock capturing technique based on the computation of a low and a high order solutions, mixed with a slope limiter
Comments: This technique is only active if 'ifct' is set to 1

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spring

Syntax: [u_t, u_dot_t, u_double_dot_t]=spring(vprel,Ppiston,pres_init0,A,Delta_t,u_t,u_dot_t,u_double_dot_t)
Description: Dynamic resolution to compute the velocity and position of the piston at each time step
Comments: Based on an implicit and non dissipative Newmark-Wilson scheme

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structure

Syntax: structure
Description: Structure resolution at each time step after extraction of the piston pressure value computed by the fluid model
Comments: none

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temperature

Syntax: [vtemp]=temperature(C_v,vsol)
Description: Computation of the temperature on each node of the fluid model, according to the fluid energy equation
Comments: Only necessary for the C-model

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timestep

Syntax: [Delta_t]=timestep(vcor,vsol,wx,vcelerity,CFL)
Description: Computation of the fluid time step to ensure the temporal stability (CFL condition)
Comments: Only necessary for the C-model

Emmanuel Lefrançois
Mechanical System Engineering Department
Université de Technologie de Compiègne
emmanuel.lefrancois@utc.fr
Jean-Paul Boufflet
Department of  Computer Sciences
Université de Technologie de Compiègne
jean-paul.boufflet@utc.fr