Systems / 01

Aerodynamics

Airflow around, through and under the body, read as pressure, momentum and wake rather than as styling.

Illustrative · simulated demo dataOUTPUT: drag coefficient (illustrative)

Airflow schematic

Side section · centreline · illustrative flow

Streamline Wake boundaryTap numbered markers or the list

Annotations — baseline

5 · Wake and tail

A blunt tail produces a tall, separated wake — the largest single contributor in this illustration.

Drag contribution in this zone (illustrative): reference

Approach

Drag is the visible cost of pushing a shape through air. We separate it by zone — nose, wheels, underbody, cooling flow and wake — so that each change can be argued from the flow field and then checked against a measurement.

Methodology

Frame the question as a budget: which zones contribute to drag, lift and cooling flow, and by how much relative to the baseline.
Use CFD to rank candidate changes, wind-tunnel testing to measure the short list, and a correlation plan to say how far each can be trusted.
Report the change in CdA (drag coefficient × frontal area) together with the test conditions, not Cd alone.

Deliverables

Zone-by-zone drag and lift budget
CFD-to-tunnel correlation plan
Pressure-tap and wake-rake instrumentation layout

Scope and constraints

Packaging, cooling and crash structures limit how far any surface can move.
Tunnel blockage, floor simulation and wheel rotation change what a result means.
Road conditions — yaw, turbulence, temperature — are never identical to the test section.

Wind tunnel and CFD, side by side

Wind tunnel and CFD, side by side
	Wind tunnel	CFD
Strength	Measures the real flow, including effects nobody modelled.	Shows the whole flow field, including where drag is generated.
Weakness	Limited by scale, blockage, floor and wheel simulation; each run is expensive.	Depends on turbulence modelling, mesh quality and boundary conditions.
Best for	Final ranking of a short list; correlation anchor.	Early exploration; understanding mechanism; many variants.
Reported as	CdA and balance, with tunnel configuration and repeatability.	CdA and fields, with mesh study and validation case.

Next: 02 Vehicle dynamics →

Airflow schematic

Side section · centreline · illustrative flow

Streamline Wake boundaryTap numbered markers or the list

Annotations — baseline

5 · Wake and tail

A blunt tail produces a tall, separated wake — the largest single contributor in this illustration.

Drag contribution in this zone (illustrative): reference

Wind tunnel

CFD

Strength

Measures the real flow, including effects nobody modelled.

Shows the whole flow field, including where drag is generated.

Weakness

Limited by scale, blockage, floor and wheel simulation; each run is expensive.

Depends on turbulence modelling, mesh quality and boundary conditions.

Best for

Final ranking of a short list; correlation anchor.

Early exploration; understanding mechanism; many variants.

Reported as

CdA and balance, with tunnel configuration and repeatability.

CdA and fields, with mesh study and validation case.