diff --git a/pyproject.toml b/pyproject.toml
index b702f2c..5288151 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -35,9 +35,6 @@ dependencies = [
 Homepage = "https://github.com/frank14f/CelerisLab"
 Repository = "https://github.com/frank14f/CelerisLab.git"
 
-[project.scripts]
-celerislab = "CelerisLab.driver:main"
-
 [tool.setuptools]
 package-dir = {"" = "src"}
 
@@ -45,4 +42,4 @@ package-dir = {"" = "src"}
 where = ["src"]
 
 [tool.setuptools.package-data]
-CelerisLab = ["kernels/*.cu", "kernels/*.h", "configs/*.json"]
+"CelerisLab.lbm" = ["kernels/*.cu", "kernels/*.h", "configs/*.json"]
diff --git a/setup.py b/setup.py
index 3c67a73..1160c69 100644
--- a/setup.py
+++ b/setup.py
@@ -14,7 +14,7 @@ setup(
     packages=find_packages(where='src'),
     package_dir={'': 'src'},
     package_data={
-        'CelerisLab': [
+        'CelerisLab.lbm': [
             'kernels/*.cu',
             'kernels/*.h',
             'configs/*.json',
@@ -37,9 +37,4 @@ setup(
         'Programming Language :: Python :: 3.10',
         'Programming Language :: Python :: 3.11',
     ],
-    entry_points={
-        'console_scripts': [
-            'celerislab=CelerisLab.driver:main',
-        ],
-    },
 )
\ No newline at end of file
diff --git a/src/CelerisLab/__init__.py b/src/CelerisLab/__init__.py
index ba87619..e64195c 100644
--- a/src/CelerisLab/__init__.py
+++ b/src/CelerisLab/__init__.py
@@ -1,24 +1,44 @@
 # CelerisLab/__init__.py
 """
-CelerisLab: GPU-Accelerated Lattice Boltzmann Method CFD Solver
+CelerisLab: GPU-Accelerated Computational Physics Simulation Library
+
+A modular framework for GPU-accelerated physics simulations including:
+- Lattice Boltzmann Method (LBM) for fluid dynamics
+- Future: Finite Element Method (FEM), Smoothed Particle Hydrodynamics (SPH), etc.
+
+Usage:
+    # Direct import of main classes
+    from CelerisLab import FlowField
+    
+    # Module-specific imports
+    from CelerisLab.lbm import FlowField
+    
+    # Namespace style
+    import CelerisLab as cl
+    solver = cl.lbm.FlowField(...)
 """
 
 __version__ = '0.2.0'
 
-# Always import utils (no pycuda dependency)
-from . import utils
+# Import submodules
+from . import common
+from . import cuda
+from . import lbm
 
-# Try to import FlowField (requires pycuda)
+# Import commonly used utilities for convenience
+from .common import utils
+
+# Attempt to import main classes for direct access
 try:
-    from .driver import FlowField
-    __all__ = ['FlowField', 'utils']
+    from .lbm import FlowField
+    __all__ = ['lbm', 'common', 'cuda', 'utils', 'FlowField', '__version__']
 except ImportError as e:
-    # PyCUDA not available, only utils module will be accessible
+    # PyCUDA not available, only submodules accessible
     import warnings
     warnings.warn(
         f"FlowField not available: {e}. "
         "Install pycuda to use the full CelerisLab functionality. "
-        "Utils module is still accessible for configuration management.",
+        "Utils and other modules are still accessible.",
         ImportWarning
     )
-    __all__ = ['utils']
\ No newline at end of file
+    __all__ = ['lbm', 'common', 'cuda', 'utils', '__version__']
diff --git a/src/CelerisLab/common/__init__.py b/src/CelerisLab/common/__init__.py
new file mode 100644
index 0000000..7663ec6
--- /dev/null
+++ b/src/CelerisLab/common/__init__.py
@@ -0,0 +1,9 @@
+# CelerisLab/common/__init__.py
+"""
+Common utilities and preprocessing functions.
+"""
+
+from . import utils
+from . import preprocess
+
+__all__ = ['utils', 'preprocess']
diff --git a/src/CelerisLab/preprocess.py b/src/CelerisLab/common/preprocess.py
similarity index 100%
rename from src/CelerisLab/preprocess.py
rename to src/CelerisLab/common/preprocess.py
diff --git a/src/CelerisLab/utils.py b/src/CelerisLab/common/utils.py
similarity index 98%
rename from src/CelerisLab/utils.py
rename to src/CelerisLab/common/utils.py
index 9410a29..a087da7 100644
--- a/src/CelerisLab/utils.py
+++ b/src/CelerisLab/common/utils.py
@@ -125,8 +125,9 @@ def find_config_file(config_filename: str, config_path: Optional[str] = None) ->
     search_paths.append(os.path.join(os.getcwd(), 'configs', config_filename))
     
     # Priority 4: Package installation location (relative to this utils.py)
-    package_root = os.path.dirname(os.path.abspath(__file__))
-    search_paths.append(os.path.join(package_root, 'configs', config_filename))
+    # configs are in lbm/configs/
+    package_root = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+    search_paths.append(os.path.join(package_root, 'lbm', 'configs', config_filename))
     
     # Search for the file
     for path in search_paths:
diff --git a/src/CelerisLab/configs/config_cuda.json b/src/CelerisLab/configs/config_cuda.json
deleted file mode 100644
index 3d4c10b..0000000
--- a/src/CelerisLab/configs/config_cuda.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-    "multi_gpu": false,
-    "gpu_connection": "NVLink",
-    "required_cuda_capability": "7.0",
-    "threads_per_block": 128,
-    "X_1U": 128,
-    "Y_1U": 32,
-    "Z_1U": 1
-}
\ No newline at end of file
diff --git a/src/CelerisLab/configs/config_flowfield.json b/src/CelerisLab/configs/config_flowfield.json
deleted file mode 100644
index 3f2f42d..0000000
--- a/src/CelerisLab/configs/config_flowfield.json
+++ /dev/null
@@ -1,13 +0,0 @@
-{
-    "data_type": "FP32",
-    "dimensionality": 2,
-    "lattice": 9,
-    "field_dim_in_U": [10, 16, 1],
-    "viscosity": 0.002,
-    "velocity": 0.01,
-    "boundary_conditions": {
-        "x": ["parabolic", "outflow"],
-        "y": ["noslip", "noslip"],
-        "z": ["none", "none"]
-    }
-}
\ No newline at end of file
diff --git a/src/CelerisLab/configs/config_gym.json b/src/CelerisLab/configs/config_gym.json
deleted file mode 100644
index 544b7b4..0000000
--- a/src/CelerisLab/configs/config_gym.json
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-    
-}
\ No newline at end of file
diff --git a/src/CelerisLab/cuda/__init__.py b/src/CelerisLab/cuda/__init__.py
new file mode 100644
index 0000000..8151d57
--- /dev/null
+++ b/src/CelerisLab/cuda/__init__.py
@@ -0,0 +1,8 @@
+# CelerisLab/cuda/__init__.py
+"""
+CUDA compiler and kernel management utilities.
+"""
+
+from . import compiler
+
+__all__ = ['compiler']
diff --git a/src/CelerisLab/compiler.py b/src/CelerisLab/cuda/compiler.py
similarity index 91%
rename from src/CelerisLab/compiler.py
rename to src/CelerisLab/cuda/compiler.py
index c51cbe5..3734d75 100644
--- a/src/CelerisLab/compiler.py
+++ b/src/CelerisLab/cuda/compiler.py
@@ -1,15 +1,16 @@
-# CelerisLab/kernels/compiler.py
+# CelerisLab/cuda/compiler.py
 
 import subprocess
 import re
 import os
 
-from .utils import FlowFieldConfig, CudaConfig
+from ..common.utils import FlowFieldConfig, CudaConfig
 
 
 def kernel_path(file_name: str) -> str:
-    current_dir = os.path.dirname(os.path.abspath(__file__))
-    return os.path.join(current_dir, "kernels", file_name)
+    # kernels are in lbm/kernels/
+    current_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+    return os.path.join(current_dir, "lbm", "kernels", file_name)
 
 
 def read_lines(file_path):
diff --git a/src/CelerisLab/lbm/__init__.py b/src/CelerisLab/lbm/__init__.py
new file mode 100644
index 0000000..0a8f33b
--- /dev/null
+++ b/src/CelerisLab/lbm/__init__.py
@@ -0,0 +1,16 @@
+# CelerisLab/lbm/__init__.py
+"""
+Lattice Boltzmann Method (LBM) module for fluid simulation.
+"""
+
+try:
+    from .driver import FlowField
+    __all__ = ['FlowField']
+except ImportError as e:
+    import warnings
+    warnings.warn(
+        f"LBM module not fully available: {e}. "
+        "Install pycuda to use the full LBM functionality.",
+        ImportWarning
+    )
+    __all__ = []
diff --git a/configs/config_cuda.json b/src/CelerisLab/lbm/configs/config_cuda.json
similarity index 100%
rename from configs/config_cuda.json
rename to src/CelerisLab/lbm/configs/config_cuda.json
diff --git a/configs/config_flowfield.json b/src/CelerisLab/lbm/configs/config_flowfield.json
similarity index 100%
rename from configs/config_flowfield.json
rename to src/CelerisLab/lbm/configs/config_flowfield.json
diff --git a/configs/config_gym.json b/src/CelerisLab/lbm/configs/config_gym.json
similarity index 100%
rename from configs/config_gym.json
rename to src/CelerisLab/lbm/configs/config_gym.json
diff --git a/src/CelerisLab/driver.py b/src/CelerisLab/lbm/driver.py
similarity index 99%
rename from src/CelerisLab/driver.py
rename to src/CelerisLab/lbm/driver.py
index 09832ad..94649f2 100644
--- a/src/CelerisLab/driver.py
+++ b/src/CelerisLab/lbm/driver.py
@@ -1,4 +1,4 @@
-# CelerisLab/driver.py
+# CelerisLab/lbm/driver.py
 
 import pycuda.driver as cuda
 import numpy as np
@@ -6,9 +6,9 @@ import struct
 from scipy.special import jv, expi
 from typing import List, Tuple, Union, Optional
 
-from . import utils
-from . import preprocess as preproc
-from . import compiler
+from ..common import utils
+from ..common import preprocess as preproc
+from ..cuda import compiler
 
 FLUID = 0b00000001
 SOLID = 0b00000010
diff --git a/src/CelerisLab/kernels/D2Q9.cu b/src/CelerisLab/lbm/kernels/D2Q9.cu
similarity index 100%
rename from src/CelerisLab/kernels/D2Q9.cu
rename to src/CelerisLab/lbm/kernels/D2Q9.cu
diff --git a/src/CelerisLab/kernels/IO.cu b/src/CelerisLab/lbm/kernels/IO.cu
similarity index 100%
rename from src/CelerisLab/kernels/IO.cu
rename to src/CelerisLab/lbm/kernels/IO.cu
diff --git a/src/CelerisLab/kernels/const.h b/src/CelerisLab/lbm/kernels/const.h
similarity index 100%
rename from src/CelerisLab/kernels/const.h
rename to src/CelerisLab/lbm/kernels/const.h
diff --git a/src/CelerisLab/kernels/kernel.cu b/src/CelerisLab/lbm/kernels/kernel.cu
similarity index 100%
rename from src/CelerisLab/kernels/kernel.cu
rename to src/CelerisLab/lbm/kernels/kernel.cu
diff --git a/src/CelerisLab/kernels/macros.h b/src/CelerisLab/lbm/kernels/macros.h
similarity index 100%
rename from src/CelerisLab/kernels/macros.h
rename to src/CelerisLab/lbm/kernels/macros.h
diff --git a/src/CelerisLab/kernels/preproc.cu b/src/CelerisLab/lbm/kernels/preproc.cu
similarity index 100%
rename from src/CelerisLab/kernels/preproc.cu
rename to src/CelerisLab/lbm/kernels/preproc.cu