Methods and systems for generating suitable meshes for hybrid RANS/LES modelling
View Patent ↗A method of generating a mesh of an object ( 11 ) that moves through a fluid medium which is used in the design or analysis of the object ( 11 ) in connection with a hybrid method combining RANS and LES comprising the following steps: a) creating an inner “C” topology ( 21 ) around the object ( 11 ) for a boundary layer description; b) creating an outer “C” topology ( 23 ) covering a space region including the separation region; c) locating the separation region and adapting to it the inner and outer “C's” topologies ( 21, 23 ) so that the outer “C” topology ( 23 ) is adapted to the size of the separated region and the inner “C” topology ( 21 ) is adapted to the size of the boundary layer; d) refining the mesh in the separation region according to the specifications of the RANS/LES method. The invention also provides a system for carrying out the method.
1. A method of generating a mesh of an object that moves through a fluid medium which is used in the design or analysis of said object in connection with a hybrid method combining RANS and LES, said hybrid method having a set of specifications, wherein said method of generating a mesh comprises the following steps:
a) creating an inner “C” topology around said object for a boundary layer description;
b) creating an outer “C” topology around the inner “C” topology covering a space region including a separation region;
c) locating the separation region intermediate the inner and outer topologies and connecting it to said inner and outer “C's” topologies so that the outer “C” topology is fixed to the size of the separated region and the inner “C” topology is fixed to the size of the boundary layer;
d) refining the mesh in the separation region according to the specifications of said RANS/LES hybrid method.
2. A method according to claim 1 , wherein the step d) includes creating cell jumps in one or more of the following locations:
a split cutting transversally the outer “C” topology before separation region;
the external boundary of the outer “C” topology;
the object side opposite to the separation region;
the downwash without upstream influence.
3. A method according to claim 1 , wherein said object is an airfoil and the flow is detached.
4. A method according to claim 3 , wherein said object is an airplane or any of its parts.
5. A system for generating a mesh of an object that moves through a fluid medium which is used in the design or analysis of said object in connection with a hybrid method combining RANS and LES, said hybrid method having a set of specifications, wherein said method of generating a mesh comprises a computer-implemented CFD model that allows the generation of said mesh in the following steps:
a) creating an inner “C” topology around said object for a boundary layer description;
b) creating an outer “C” topology around the inner “C” topology covering a space region including a separation region;
c) locating the separation region intermediate the inner and outer topologies and connecting it to said inner and outer “C's” topologies so that the outer “C” topology is fixed to the size of the separated region and the inner “C” topology is fixed to the size of the boundary layer;
d) refining the mesh in the separation region according to the specifications of said BANS/LES hybrid method.
6. A system according to claim 5 , wherein step d) includes creating cell jumps in one or more of the following locations:
a split cutting transversally the outer “C” topology before the separation region;
the external boundary of the outer “C” topology;
the object side opposite to the separation region;
the downwash without upstream influence.
7. A system according to claim 5 , wherein said object is an airfoil and the flow is detached.
8. A system according to claim 7 , wherein said object is an airplane or any of its parts.