1. Status Report of New Issues TF –CFD* sub wg
WLTP-24-10e
CFD Report
Status Report of New Issues TF –CFD* sub wg
*CFD: Computational Fluid Dynamics method, method to simulate aero drag
Sep., 2018
Mayumi “Sophie” Morimoto (JASIC)

2. Background of CFD discussion/Status
Review of 22nd WLTP IWG in April 2018
Sub working group members requested to CPs/TAs and IWG to join the meeting.
Because of lack of resources, WLTP IWG decided to postpone the discussion of CFD sub working group until GTR15 Amd5 discussion finish.
During the CFD discussion on May
Even with WLTP IWG decision, some manufacturers strongly requested discussion even without TA/CPs, to make some proposals on Spring They also did not accept discussion between manufacturers within each regions.
Therefore, web meeting of CFD sub wg in UN level was held on 5th Sep.
Status & Schedule
2 meetings were held after April WLTP IWG.
Next meeting will be held at late November or early December

3. Discussion Points/Comments raised by members
Certification criteria of CFD simulation model
Most of the members request to delete current requirements/criterion and add more reasonable criterion and make text clear.
Some members have ideas on what to write on the text instead of current requirement. Those proposals will be discussed at next meeting.
Certification demonstration/process of CFD simulation model
Whether to write in details or just write “Shall be discussed with responsible authority” is under discussion.
Certification process of vehicle aero drag using CFD simulation model
Re-certification criteria of CFD simulation model
Requested to define more clearly. This is also under discussion.
Certification scope using CFD simulation model
There are comment to make specific family for CFD since R/L family is not relevant to CFD.
Certification motivation using CFD simulation model
*See WLTP-24-10e Appendix1 for details.
Technical discussions are on going in CFD sub-working group.

4. Thank you very much for your attention!