This experiment focuses on the development and measurement of atmospheric boundary layer (ABL) profiles to simulate different terrain categories and their transitions as defined in Eurocode. The tests were performed at the closed-circuit wind-tunnel facility of TU Eindhoven. The ABLs are developed using rows of roughness elements positioned along the wind tunnel fetch of 21.9m length. The roughness elements were arranged in rows spaced 0.3 m apart along the entire fetch, beginning 0.6 m upstream of the building center. Additional rows of roughness elements were added 0.6 m downstream of the building center to assure that the building model is embedded in roughness elements. The velocity measurements for the ABL were made at 19 heights (0.03 m to 0.763 m) in reduced scale. For all 27 modelled approach flows, velocity measurements were taken at a distance of 1.8 m upstream of the building center (location P1). For profiles A1, A2, B1, B2, B3, C1, and C2 (described below), additional velocity measurements were also made at location P2, which is located 0.15 m upstream and 0.75 m laterally offset from the building center, i.e., closer to the building.

The experiment consists of two main parts:

1. Generation of three distinct ABL profiles: Three baseline profiles were developed to represent Eurocode terrain categories:

Profile A: Terrain Category II – 72 roughness elements of size 2 × 2 cm²

Profile B: Terrain Category III – 72 roughness elements of size 4 × 4 cm²

Profile C: Terrain Category IV – 72 roughness elements of size 6 × 6 cm²

2. Development of Transitional Profiles Between Terrains: To study the transition effects between different terrain types, transitional profiles were designed by gradually replacing roughness elements from one profile with those from another:

- Transition from Profile A to Profile B (Profiles A1–A8): Incremental substitution of 2 × 2 cm² elements with 4 × 4 cm² elements.

- Transition from Profile B to Profile C (Profiles B1–B8): Incremental substitution of 4 × 4 cm² elements with 6 × 6 cm² elements.

- Transition from Profile A to Profile C (Profiles C1–C8): Incremental substitution of 2 × 2 cm² elements with 6 × 6 cm² elements.

Layout of roughness elements for all profiles included in file Roughness Element Layout.txt

For each approach flow ABL developed (Profiles A, A1-A8, B, B1-B8, C and C1-C8), surface pressure was measured on the facades and roof of the building model in order to quantify the effect of wind flow over different terrain conditions on wind pressures on buildings. The facades were instrumented with pressure taps numbered 1 to 240, while taps 241 to 252 were installed on the roof. Pressure data was recorded continuously for 3 minutes at a sampling frequency of 800 Hz. The tests were conducted for three wind directions: 0°, 45°, and 90° for each ABL developed. Additional Reynolds number independency tests were also performed for six scenarios.